/****************************************************************************
 *
 * freetype.h
 *
 *   FreeType high-level API and common types (specification only).
 *
 * Copyright (C) 1996-2019 by
 * David Turner, Robert Wilhelm, and Werner Lemberg.
 *
 * This file is part of the FreeType project, and may only be used,
 * modified, and distributed under the terms of the FreeType project
 * license, LICENSE.TXT.  By continuing to use, modify, or distribute
 * this file you indicate that you have read the license and
 * understand and accept it fully.
 *
 */

#ifndef FREETYPE_H_
#define FREETYPE_H_

#ifndef FT_FREETYPE_H
#error "`ft2build.h' hasn't been included yet!"
#error "Please always use macros to include FreeType header files."
#error "Example:"
#error "  #include <ft2build.h>"
#error "  #include FT_FREETYPE_H"
#endif

#include <ft2build.h>
#include FT_CONFIG_CONFIG_H
#include FT_TYPES_H
#include FT_ERRORS_H

FT_BEGIN_HEADER

/**************************************************************************
 *
 * @section:
 *   header_inclusion
 *
 * @title:
 *   FreeType's header inclusion scheme
 *
 * @abstract:
 *   How client applications should include FreeType header files.
 *
 * @description:
 *   To be as flexible as possible (and for historical reasons), FreeType
 *   uses a very special inclusion scheme to load header files, for example
 *
 *   ```
 *     #include <ft2build.h>
 *
 *     #include FT_FREETYPE_H
 *     #include FT_OUTLINE_H
 *   ```
 *
 *   A compiler and its preprocessor only needs an include path to find the
 *   file `ft2build.h`; the exact locations and names of the other FreeType
 *   header files are hidden by @header_file_macros, loaded by
 *   `ft2build.h`.  The API documentation always gives the header macro
 *   name needed for a particular function.
 *
 */

/**************************************************************************
 *
 * @section:
 *   user_allocation
 *
 * @title:
 *   User allocation
 *
 * @abstract:
 *   How client applications should allocate FreeType data structures.
 *
 * @description:
 *   FreeType assumes that structures allocated by the user and passed as
 *   arguments are zeroed out except for the actual data.  In other words,
 *   it is recommended to use `calloc` (or variants of it) instead of
 *   `malloc` for allocation.
 *
 */

/*************************************************************************/
/*************************************************************************/
/*                                                                       */
/*                        B A S I C   T Y P E S                          */
/*                                                                       */
/*************************************************************************/
/*************************************************************************/

/**************************************************************************
 *
 * @section:
 *   base_interface
 *
 * @title:
 *   Base Interface
 *
 * @abstract:
 *   The FreeType~2 base font interface.
 *
 * @description:
 *   This section describes the most important public high-level API
 *   functions of FreeType~2.
 *
 * @order:
 *   FT_Library
 *   FT_Face
 *   FT_Size
 *   FT_GlyphSlot
 *   FT_CharMap
 *   FT_Encoding
 *   FT_ENC_TAG
 *
 *   FT_FaceRec
 *
 *   FT_FACE_FLAG_SCALABLE
 *   FT_FACE_FLAG_FIXED_SIZES
 *   FT_FACE_FLAG_FIXED_WIDTH
 *   FT_FACE_FLAG_HORIZONTAL
 *   FT_FACE_FLAG_VERTICAL
 *   FT_FACE_FLAG_COLOR
 *   FT_FACE_FLAG_SFNT
 *   FT_FACE_FLAG_CID_KEYED
 *   FT_FACE_FLAG_TRICKY
 *   FT_FACE_FLAG_KERNING
 *   FT_FACE_FLAG_MULTIPLE_MASTERS
 *   FT_FACE_FLAG_VARIATION
 *   FT_FACE_FLAG_GLYPH_NAMES
 *   FT_FACE_FLAG_EXTERNAL_STREAM
 *   FT_FACE_FLAG_HINTER
 *
 *   FT_HAS_HORIZONTAL
 *   FT_HAS_VERTICAL
 *   FT_HAS_KERNING
 *   FT_HAS_FIXED_SIZES
 *   FT_HAS_GLYPH_NAMES
 *   FT_HAS_COLOR
 *   FT_HAS_MULTIPLE_MASTERS
 *
 *   FT_IS_SFNT
 *   FT_IS_SCALABLE
 *   FT_IS_FIXED_WIDTH
 *   FT_IS_CID_KEYED
 *   FT_IS_TRICKY
 *   FT_IS_NAMED_INSTANCE
 *   FT_IS_VARIATION
 *
 *   FT_STYLE_FLAG_BOLD
 *   FT_STYLE_FLAG_ITALIC
 *
 *   FT_SizeRec
 *   FT_Size_Metrics
 *
 *   FT_GlyphSlotRec
 *   FT_Glyph_Metrics
 *   FT_SubGlyph
 *
 *   FT_Bitmap_Size
 *
 *   FT_Init_FreeType
 *   FT_Done_FreeType
 *
 *   FT_New_Face
 *   FT_Done_Face
 *   FT_Reference_Face
 *   FT_New_Memory_Face
 *   FT_Face_Properties
 *   FT_Open_Face
 *   FT_Open_Args
 *   FT_Parameter
 *   FT_Attach_File
 *   FT_Attach_Stream
 *
 *   FT_Set_Char_Size
 *   FT_Set_Pixel_Sizes
 *   FT_Request_Size
 *   FT_Select_Size
 *   FT_Size_Request_Type
 *   FT_Size_RequestRec
 *   FT_Size_Request
 *   FT_Set_Transform
 *   FT_Load_Glyph
 *   FT_Get_Char_Index
 *   FT_Get_First_Char
 *   FT_Get_Next_Char
 *   FT_Get_Name_Index
 *   FT_Load_Char
 *
 *   FT_OPEN_MEMORY
 *   FT_OPEN_STREAM
 *   FT_OPEN_PATHNAME
 *   FT_OPEN_DRIVER
 *   FT_OPEN_PARAMS
 *
 *   FT_LOAD_DEFAULT
 *   FT_LOAD_RENDER
 *   FT_LOAD_MONOCHROME
 *   FT_LOAD_LINEAR_DESIGN
 *   FT_LOAD_NO_SCALE
 *   FT_LOAD_NO_HINTING
 *   FT_LOAD_NO_BITMAP
 *   FT_LOAD_NO_AUTOHINT
 *   FT_LOAD_COLOR
 *
 *   FT_LOAD_VERTICAL_LAYOUT
 *   FT_LOAD_IGNORE_TRANSFORM
 *   FT_LOAD_FORCE_AUTOHINT
 *   FT_LOAD_NO_RECURSE
 *   FT_LOAD_PEDANTIC
 *
 *   FT_LOAD_TARGET_NORMAL
 *   FT_LOAD_TARGET_LIGHT
 *   FT_LOAD_TARGET_MONO
 *   FT_LOAD_TARGET_LCD
 *   FT_LOAD_TARGET_LCD_V
 *
 *   FT_LOAD_TARGET_MODE
 *
 *   FT_Render_Glyph
 *   FT_Render_Mode
 *   FT_Get_Kerning
 *   FT_Kerning_Mode
 *   FT_Get_Track_Kerning
 *   FT_Get_Glyph_Name
 *   FT_Get_Postscript_Name
 *
 *   FT_CharMapRec
 *   FT_Select_Charmap
 *   FT_Set_Charmap
 *   FT_Get_Charmap_Index
 *
 *   FT_Get_FSType_Flags
 *   FT_Get_SubGlyph_Info
 *
 *   FT_Face_Internal
 *   FT_Size_Internal
 *   FT_Slot_Internal
 *
 *   FT_FACE_FLAG_XXX
 *   FT_STYLE_FLAG_XXX
 *   FT_OPEN_XXX
 *   FT_LOAD_XXX
 *   FT_LOAD_TARGET_XXX
 *   FT_SUBGLYPH_FLAG_XXX
 *   FT_FSTYPE_XXX
 *
 *   FT_HAS_FAST_GLYPHS
 *
 */

/**************************************************************************
 *
 * @struct:
 *   FT_Glyph_Metrics
 *
 * @description:
 *   A structure to model the metrics of a single glyph.  The values are
 *   expressed in 26.6 fractional pixel format; if the flag
 *   @FT_LOAD_NO_SCALE has been used while loading the glyph, values are
 *   expressed in font units instead.
 *
 * @fields:
 *   width ::
 *     The glyph's width.
 *
 *   height ::
 *     The glyph's height.
 *
 *   horiBearingX ::
 *     Left side bearing for horizontal layout.
 *
 *   horiBearingY ::
 *     Top side bearing for horizontal layout.
 *
 *   horiAdvance ::
 *     Advance width for horizontal layout.
 *
 *   vertBearingX ::
 *     Left side bearing for vertical layout.
 *
 *   vertBearingY ::
 *     Top side bearing for vertical layout.  Larger positive values mean
 *     further below the vertical glyph origin.
 *
 *   vertAdvance ::
 *     Advance height for vertical layout.  Positive values mean the glyph
 *     has a positive advance downward.
 *
 * @note:
 *   If not disabled with @FT_LOAD_NO_HINTING, the values represent
 *   dimensions of the hinted glyph (in case hinting is applicable).
 *
 *   Stroking a glyph with an outside border does not increase
 *   `horiAdvance` or `vertAdvance`; you have to manually adjust these
 *   values to account for the added width and height.
 *
 *   FreeType doesn't use the 'VORG' table data for CFF fonts because it
 *   doesn't have an interface to quickly retrieve the glyph height.  The
 *   y~coordinate of the vertical origin can be simply computed as
 *   `vertBearingY + height` after loading a glyph.
 */
typedef struct FT_Glyph_Metrics_ {
	FT_Pos width;
	FT_Pos height;

	FT_Pos horiBearingX;
	FT_Pos horiBearingY;
	FT_Pos horiAdvance;

	FT_Pos vertBearingX;
	FT_Pos vertBearingY;
	FT_Pos vertAdvance;

} FT_Glyph_Metrics;

/**************************************************************************
 *
 * @struct:
 *   FT_Bitmap_Size
 *
 * @description:
 *   This structure models the metrics of a bitmap strike (i.e., a set of
 *   glyphs for a given point size and resolution) in a bitmap font.  It is
 *   used for the `available_sizes` field of @FT_Face.
 *
 * @fields:
 *   height ::
 *     The vertical distance, in pixels, between two consecutive baselines.
 *     It is always positive.
 *
 *   width ::
 *     The average width, in pixels, of all glyphs in the strike.
 *
 *   size ::
 *     The nominal size of the strike in 26.6 fractional points.  This
 *     field is not very useful.
 *
 *   x_ppem ::
 *     The horizontal ppem (nominal width) in 26.6 fractional pixels.
 *
 *   y_ppem ::
 *     The vertical ppem (nominal height) in 26.6 fractional pixels.
 *
 * @note:
 *   Windows FNT:
 *     The nominal size given in a FNT font is not reliable.  If the driver
 *     finds it incorrect, it sets `size` to some calculated values, and
 *     `x_ppem` and `y_ppem` to the pixel width and height given in the
 *     font, respectively.
 *
 *   TrueType embedded bitmaps:
 *     `size`, `width`, and `height` values are not contained in the bitmap
 *     strike itself.  They are computed from the global font parameters.
 */
typedef struct FT_Bitmap_Size_ {
	FT_Short height;
	FT_Short width;

	FT_Pos size;

	FT_Pos x_ppem;
	FT_Pos y_ppem;

} FT_Bitmap_Size;

/*************************************************************************/
/*************************************************************************/
/*                                                                       */
/*                     O B J E C T   C L A S S E S                       */
/*                                                                       */
/*************************************************************************/
/*************************************************************************/

/**************************************************************************
 *
 * @type:
 *   FT_Library
 *
 * @description:
 *   A handle to a FreeType library instance.  Each 'library' is completely
 *   independent from the others; it is the 'root' of a set of objects like
 *   fonts, faces, sizes, etc.
 *
 *   It also embeds a memory manager (see @FT_Memory), as well as a
 *   scan-line converter object (see @FT_Raster).
 *
 *   [Since 2.5.6] In multi-threaded applications it is easiest to use one
 *   `FT_Library` object per thread.  In case this is too cumbersome, a
 *   single `FT_Library` object across threads is possible also, as long as
 *   a mutex lock is used around @FT_New_Face and @FT_Done_Face.
 *
 * @note:
 *   Library objects are normally created by @FT_Init_FreeType, and
 *   destroyed with @FT_Done_FreeType.  If you need reference-counting
 *   (cf. @FT_Reference_Library), use @FT_New_Library and @FT_Done_Library.
 */
typedef struct FT_LibraryRec_ *FT_Library;

/**************************************************************************
 *
 * @section:
 *   module_management
 *
 */

/**************************************************************************
 *
 * @type:
 *   FT_Module
 *
 * @description:
 *   A handle to a given FreeType module object.  A module can be a font
 *   driver, a renderer, or anything else that provides services to the
 *   former.
 */
typedef struct FT_ModuleRec_ *FT_Module;

/**************************************************************************
 *
 * @type:
 *   FT_Driver
 *
 * @description:
 *   A handle to a given FreeType font driver object.  A font driver is a
 *   module capable of creating faces from font files.
 */
typedef struct FT_DriverRec_ *FT_Driver;

/**************************************************************************
 *
 * @type:
 *   FT_Renderer
 *
 * @description:
 *   A handle to a given FreeType renderer.  A renderer is a module in
 *   charge of converting a glyph's outline image to a bitmap.  It supports
 *   a single glyph image format, and one or more target surface depths.
 */
typedef struct FT_RendererRec_ *FT_Renderer;

/**************************************************************************
 *
 * @section:
 *   base_interface
 *
 */

/**************************************************************************
 *
 * @type:
 *   FT_Face
 *
 * @description:
 *   A handle to a typographic face object.  A face object models a given
 *   typeface, in a given style.
 *
 * @note:
 *   A face object also owns a single @FT_GlyphSlot object, as well as one
 *   or more @FT_Size objects.
 *
 *   Use @FT_New_Face or @FT_Open_Face to create a new face object from a
 *   given filepath or a custom input stream.
 *
 *   Use @FT_Done_Face to destroy it (along with its slot and sizes).
 *
 *   An `FT_Face` object can only be safely used from one thread at a time.
 *   Similarly, creation and destruction of `FT_Face` with the same
 *   @FT_Library object can only be done from one thread at a time.  On the
 *   other hand, functions like @FT_Load_Glyph and its siblings are
 *   thread-safe and do not need the lock to be held as long as the same
 *   `FT_Face` object is not used from multiple threads at the same time.
 *
 * @also:
 *   See @FT_FaceRec for the publicly accessible fields of a given face
 *   object.
 */
typedef struct FT_FaceRec_ *FT_Face;

/**************************************************************************
 *
 * @type:
 *   FT_Size
 *
 * @description:
 *   A handle to an object that models a face scaled to a given character
 *   size.
 *
 * @note:
 *   An @FT_Face has one _active_ @FT_Size object that is used by functions
 *   like @FT_Load_Glyph to determine the scaling transformation that in
 *   turn is used to load and hint glyphs and metrics.
 *
 *   You can use @FT_Set_Char_Size, @FT_Set_Pixel_Sizes, @FT_Request_Size
 *   or even @FT_Select_Size to change the content (i.e., the scaling
 *   values) of the active @FT_Size.
 *
 *   You can use @FT_New_Size to create additional size objects for a given
 *   @FT_Face, but they won't be used by other functions until you activate
 *   it through @FT_Activate_Size.  Only one size can be activated at any
 *   given time per face.
 *
 * @also:
 *   See @FT_SizeRec for the publicly accessible fields of a given size
 *   object.
 */
typedef struct FT_SizeRec_ *FT_Size;

/**************************************************************************
 *
 * @type:
 *   FT_GlyphSlot
 *
 * @description:
 *   A handle to a given 'glyph slot'.  A slot is a container that can hold
 *   any of the glyphs contained in its parent face.
 *
 *   In other words, each time you call @FT_Load_Glyph or @FT_Load_Char,
 *   the slot's content is erased by the new glyph data, i.e., the glyph's
 *   metrics, its image (bitmap or outline), and other control information.
 *
 * @also:
 *   See @FT_GlyphSlotRec for the publicly accessible glyph fields.
 */
typedef struct FT_GlyphSlotRec_ *FT_GlyphSlot;

/**************************************************************************
 *
 * @type:
 *   FT_CharMap
 *
 * @description:
 *   A handle to a character map (usually abbreviated to 'charmap').  A
 *   charmap is used to translate character codes in a given encoding into
 *   glyph indexes for its parent's face.  Some font formats may provide
 *   several charmaps per font.
 *
 *   Each face object owns zero or more charmaps, but only one of them can
 *   be 'active', providing the data used by @FT_Get_Char_Index or
 *   @FT_Load_Char.
 *
 *   The list of available charmaps in a face is available through the
 *   `face->num_charmaps` and `face->charmaps` fields of @FT_FaceRec.
 *
 *   The currently active charmap is available as `face->charmap`.  You
 *   should call @FT_Set_Charmap to change it.
 *
 * @note:
 *   When a new face is created (either through @FT_New_Face or
 *   @FT_Open_Face), the library looks for a Unicode charmap within the
 *   list and automatically activates it.  If there is no Unicode charmap,
 *   FreeType doesn't set an 'active' charmap.
 *
 * @also:
 *   See @FT_CharMapRec for the publicly accessible fields of a given
 *   character map.
 */
typedef struct FT_CharMapRec_ *FT_CharMap;

/**************************************************************************
 *
 * @macro:
 *   FT_ENC_TAG
 *
 * @description:
 *   This macro converts four-letter tags into an unsigned long.  It is
 *   used to define 'encoding' identifiers (see @FT_Encoding).
 *
 * @note:
 *   Since many 16-bit compilers don't like 32-bit enumerations, you should
 *   redefine this macro in case of problems to something like this:
 *
 *   ```
 *     #define FT_ENC_TAG( value, a, b, c, d )  value
 *   ```
 *
 *   to get a simple enumeration without assigning special numbers.
 */

#ifndef FT_ENC_TAG
#define FT_ENC_TAG(value, a, b, c, d)                                                              \
	value =                                                                                        \
	    (((FT_UInt32)(a) << 24) | ((FT_UInt32)(b) << 16) | ((FT_UInt32)(c) << 8) | (FT_UInt32)(d))

#endif /* FT_ENC_TAG */

/**************************************************************************
 *
 * @enum:
 *   FT_Encoding
 *
 * @description:
 *   An enumeration to specify character sets supported by charmaps.  Used
 *   in the @FT_Select_Charmap API function.
 *
 * @note:
 *   Despite the name, this enumeration lists specific character
 *   repertories (i.e., charsets), and not text encoding methods (e.g.,
 *   UTF-8, UTF-16, etc.).
 *
 *   Other encodings might be defined in the future.
 *
 * @values:
 *   FT_ENCODING_NONE ::
 *     The encoding value~0 is reserved for all formats except BDF, PCF,
 *     and Windows FNT; see below for more information.
 *
 *   FT_ENCODING_UNICODE ::
 *     The Unicode character set.  This value covers all versions of the
 *     Unicode repertoire, including ASCII and Latin-1.  Most fonts include
 *     a Unicode charmap, but not all of them.
 *
 *     For example, if you want to access Unicode value U+1F028 (and the
 *     font contains it), use value 0x1F028 as the input value for
 *     @FT_Get_Char_Index.
 *
 *   FT_ENCODING_MS_SYMBOL ::
 *     Microsoft Symbol encoding, used to encode mathematical symbols and
 *     wingdings.  For more information, see
 *     'https://www.microsoft.com/typography/otspec/recom.htm#non-standard-symbol-fonts',
 *     'http://www.kostis.net/charsets/symbol.htm', and
 *     'http://www.kostis.net/charsets/wingding.htm'.
 *
 *     This encoding uses character codes from the PUA (Private Unicode
 *     Area) in the range U+F020-U+F0FF.
 *
 *   FT_ENCODING_SJIS ::
 *     Shift JIS encoding for Japanese.  More info at
 *     'https://en.wikipedia.org/wiki/Shift_JIS'.  See note on multi-byte
 *     encodings below.
 *
 *   FT_ENCODING_PRC ::
 *     Corresponds to encoding systems mainly for Simplified Chinese as
 *     used in People's Republic of China (PRC).  The encoding layout is
 *     based on GB~2312 and its supersets GBK and GB~18030.
 *
 *   FT_ENCODING_BIG5 ::
 *     Corresponds to an encoding system for Traditional Chinese as used in
 *     Taiwan and Hong Kong.
 *
 *   FT_ENCODING_WANSUNG ::
 *     Corresponds to the Korean encoding system known as Extended Wansung
 *     (MS Windows code page 949).  For more information see
 *     'https://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WindowsBestFit/bestfit949.txt'.
 *
 *   FT_ENCODING_JOHAB ::
 *     The Korean standard character set (KS~C 5601-1992), which
 *     corresponds to MS Windows code page 1361.  This character set
 *     includes all possible Hangul character combinations.
 *
 *   FT_ENCODING_ADOBE_LATIN_1 ::
 *     Corresponds to a Latin-1 encoding as defined in a Type~1 PostScript
 *     font.  It is limited to 256 character codes.
 *
 *   FT_ENCODING_ADOBE_STANDARD ::
 *     Adobe Standard encoding, as found in Type~1, CFF, and OpenType/CFF
 *     fonts.  It is limited to 256 character codes.
 *
 *   FT_ENCODING_ADOBE_EXPERT ::
 *     Adobe Expert encoding, as found in Type~1, CFF, and OpenType/CFF
 *     fonts.  It is limited to 256 character codes.
 *
 *   FT_ENCODING_ADOBE_CUSTOM ::
 *     Corresponds to a custom encoding, as found in Type~1, CFF, and
 *     OpenType/CFF fonts.  It is limited to 256 character codes.
 *
 *   FT_ENCODING_APPLE_ROMAN ::
 *     Apple roman encoding.  Many TrueType and OpenType fonts contain a
 *     charmap for this 8-bit encoding, since older versions of Mac OS are
 *     able to use it.
 *
 *   FT_ENCODING_OLD_LATIN_2 ::
 *     This value is deprecated and was neither used nor reported by
 *     FreeType.  Don't use or test for it.
 *
 *   FT_ENCODING_MS_SJIS ::
 *     Same as FT_ENCODING_SJIS.  Deprecated.
 *
 *   FT_ENCODING_MS_GB2312 ::
 *     Same as FT_ENCODING_PRC.  Deprecated.
 *
 *   FT_ENCODING_MS_BIG5 ::
 *     Same as FT_ENCODING_BIG5.  Deprecated.
 *
 *   FT_ENCODING_MS_WANSUNG ::
 *     Same as FT_ENCODING_WANSUNG.  Deprecated.
 *
 *   FT_ENCODING_MS_JOHAB ::
 *     Same as FT_ENCODING_JOHAB.  Deprecated.
 *
 * @note:
 *   By default, FreeType enables a Unicode charmap and tags it with
 *   `FT_ENCODING_UNICODE` when it is either provided or can be generated
 *   from PostScript glyph name dictionaries in the font file.  All other
 *   encodings are considered legacy and tagged only if explicitly defined
 *   in the font file.  Otherwise, `FT_ENCODING_NONE` is used.
 *
 *   `FT_ENCODING_NONE` is set by the BDF and PCF drivers if the charmap is
 *   neither Unicode nor ISO-8859-1 (otherwise it is set to
 *   `FT_ENCODING_UNICODE`).  Use @FT_Get_BDF_Charset_ID to find out which
 *   encoding is really present.  If, for example, the `cs_registry` field
 *   is 'KOI8' and the `cs_encoding` field is 'R', the font is encoded in
 *   KOI8-R.
 *
 *   `FT_ENCODING_NONE` is always set (with a single exception) by the
 *   winfonts driver.  Use @FT_Get_WinFNT_Header and examine the `charset`
 *   field of the @FT_WinFNT_HeaderRec structure to find out which encoding
 *   is really present.  For example, @FT_WinFNT_ID_CP1251 (204) means
 *   Windows code page 1251 (for Russian).
 *
 *   `FT_ENCODING_NONE` is set if `platform_id` is @TT_PLATFORM_MACINTOSH
 *   and `encoding_id` is not `TT_MAC_ID_ROMAN` (otherwise it is set to
 *   `FT_ENCODING_APPLE_ROMAN`).
 *
 *   If `platform_id` is @TT_PLATFORM_MACINTOSH, use the function
 *   @FT_Get_CMap_Language_ID to query the Mac language ID that may be
 *   needed to be able to distinguish Apple encoding variants.  See
 *
 *     https://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/Readme.txt
 *
 *   to get an idea how to do that.  Basically, if the language ID is~0,
 *   don't use it, otherwise subtract 1 from the language ID.  Then examine
 *   `encoding_id`.  If, for example, `encoding_id` is `TT_MAC_ID_ROMAN`
 *   and the language ID (minus~1) is `TT_MAC_LANGID_GREEK`, it is the
 *   Greek encoding, not Roman.  `TT_MAC_ID_ARABIC` with
 *   `TT_MAC_LANGID_FARSI` means the Farsi variant the Arabic encoding.
 */
typedef enum FT_Encoding_ {
	FT_ENC_TAG(FT_ENCODING_NONE, 0, 0, 0, 0),

	FT_ENC_TAG(FT_ENCODING_MS_SYMBOL, 's', 'y', 'm', 'b'),
	FT_ENC_TAG(FT_ENCODING_UNICODE, 'u', 'n', 'i', 'c'),

	FT_ENC_TAG(FT_ENCODING_SJIS, 's', 'j', 'i', 's'),
	FT_ENC_TAG(FT_ENCODING_PRC, 'g', 'b', ' ', ' '),
	FT_ENC_TAG(FT_ENCODING_BIG5, 'b', 'i', 'g', '5'),
	FT_ENC_TAG(FT_ENCODING_WANSUNG, 'w', 'a', 'n', 's'),
	FT_ENC_TAG(FT_ENCODING_JOHAB, 'j', 'o', 'h', 'a'),

	/* for backward compatibility */
	FT_ENCODING_GB2312 = FT_ENCODING_PRC,
	FT_ENCODING_MS_SJIS = FT_ENCODING_SJIS,
	FT_ENCODING_MS_GB2312 = FT_ENCODING_PRC,
	FT_ENCODING_MS_BIG5 = FT_ENCODING_BIG5,
	FT_ENCODING_MS_WANSUNG = FT_ENCODING_WANSUNG,
	FT_ENCODING_MS_JOHAB = FT_ENCODING_JOHAB,

	FT_ENC_TAG(FT_ENCODING_ADOBE_STANDARD, 'A', 'D', 'O', 'B'),
	FT_ENC_TAG(FT_ENCODING_ADOBE_EXPERT, 'A', 'D', 'B', 'E'),
	FT_ENC_TAG(FT_ENCODING_ADOBE_CUSTOM, 'A', 'D', 'B', 'C'),
	FT_ENC_TAG(FT_ENCODING_ADOBE_LATIN_1, 'l', 'a', 't', '1'),

	FT_ENC_TAG(FT_ENCODING_OLD_LATIN_2, 'l', 'a', 't', '2'),

	FT_ENC_TAG(FT_ENCODING_APPLE_ROMAN, 'a', 'r', 'm', 'n')

} FT_Encoding;

/* these constants are deprecated; use the corresponding `FT_Encoding` */
/* values instead                                                      */
#define ft_encoding_none FT_ENCODING_NONE
#define ft_encoding_unicode FT_ENCODING_UNICODE
#define ft_encoding_symbol FT_ENCODING_MS_SYMBOL
#define ft_encoding_latin_1 FT_ENCODING_ADOBE_LATIN_1
#define ft_encoding_latin_2 FT_ENCODING_OLD_LATIN_2
#define ft_encoding_sjis FT_ENCODING_SJIS
#define ft_encoding_gb2312 FT_ENCODING_PRC
#define ft_encoding_big5 FT_ENCODING_BIG5
#define ft_encoding_wansung FT_ENCODING_WANSUNG
#define ft_encoding_johab FT_ENCODING_JOHAB

#define ft_encoding_adobe_standard FT_ENCODING_ADOBE_STANDARD
#define ft_encoding_adobe_expert FT_ENCODING_ADOBE_EXPERT
#define ft_encoding_adobe_custom FT_ENCODING_ADOBE_CUSTOM
#define ft_encoding_apple_roman FT_ENCODING_APPLE_ROMAN

/**************************************************************************
 *
 * @struct:
 *   FT_CharMapRec
 *
 * @description:
 *   The base charmap structure.
 *
 * @fields:
 *   face ::
 *     A handle to the parent face object.
 *
 *   encoding ::
 *     An @FT_Encoding tag identifying the charmap.  Use this with
 *     @FT_Select_Charmap.
 *
 *   platform_id ::
 *     An ID number describing the platform for the following encoding ID.
 *     This comes directly from the TrueType specification and gets
 *     emulated for other formats.
 *
 *   encoding_id ::
 *     A platform-specific encoding number.  This also comes from the
 *     TrueType specification and gets emulated similarly.
 */
typedef struct FT_CharMapRec_ {
	FT_Face face;
	FT_Encoding encoding;
	FT_UShort platform_id;
	FT_UShort encoding_id;

} FT_CharMapRec;

/*************************************************************************/
/*************************************************************************/
/*                                                                       */
/*                 B A S E   O B J E C T   C L A S S E S                 */
/*                                                                       */
/*************************************************************************/
/*************************************************************************/

/**************************************************************************
 *
 * @type:
 *   FT_Face_Internal
 *
 * @description:
 *   An opaque handle to an `FT_Face_InternalRec` structure that models the
 *   private data of a given @FT_Face object.
 *
 *   This structure might change between releases of FreeType~2 and is not
 *   generally available to client applications.
 */
typedef struct FT_Face_InternalRec_ *FT_Face_Internal;

/**************************************************************************
 *
 * @struct:
 *   FT_FaceRec
 *
 * @description:
 *   FreeType root face class structure.  A face object models a typeface
 *   in a font file.
 *
 * @fields:
 *   num_faces ::
 *     The number of faces in the font file.  Some font formats can have
 *     multiple faces in a single font file.
 *
 *   face_index ::
 *     This field holds two different values.  Bits 0-15 are the index of
 *     the face in the font file (starting with value~0).  They are set
 *     to~0 if there is only one face in the font file.
 *
 *     [Since 2.6.1] Bits 16-30 are relevant to GX and OpenType variation
 *     fonts only, holding the named instance index for the current face
 *     index (starting with value~1; value~0 indicates font access without
 *     a named instance).  For non-variation fonts, bits 16-30 are ignored.
 *     If we have the third named instance of face~4, say, `face_index` is
 *     set to 0x00030004.
 *
 *     Bit 31 is always zero (this is, `face_index` is always a positive
 *     value).
 *
 *     [Since 2.9] Changing the design coordinates with
 *     @FT_Set_Var_Design_Coordinates or @FT_Set_Var_Blend_Coordinates does
 *     not influence the named instance index value (only
 *     @FT_Set_Named_Instance does that).
 *
 *   face_flags ::
 *     A set of bit flags that give important information about the face;
 *     see @FT_FACE_FLAG_XXX for the details.
 *
 *   style_flags ::
 *     The lower 16~bits contain a set of bit flags indicating the style of
 *     the face; see @FT_STYLE_FLAG_XXX for the details.
 *
 *     [Since 2.6.1] Bits 16-30 hold the number of named instances
 *     available for the current face if we have a GX or OpenType variation
 *     (sub)font.  Bit 31 is always zero (this is, `style_flags` is always
 *     a positive value).  Note that a variation font has always at least
 *     one named instance, namely the default instance.
 *
 *   num_glyphs ::
 *     The number of glyphs in the face.  If the face is scalable and has
 *     sbits (see `num_fixed_sizes`), it is set to the number of outline
 *     glyphs.
 *
 *     For CID-keyed fonts (not in an SFNT wrapper) this value gives the
 *     highest CID used in the font.
 *
 *   family_name ::
 *     The face's family name.  This is an ASCII string, usually in
 *     English, that describes the typeface's family (like 'Times New
 *     Roman', 'Bodoni', 'Garamond', etc).  This is a least common
 *     denominator used to list fonts.  Some formats (TrueType & OpenType)
 *     provide localized and Unicode versions of this string.  Applications
 *     should use the format-specific interface to access them.  Can be
 *     `NULL` (e.g., in fonts embedded in a PDF file).
 *
 *     In case the font doesn't provide a specific family name entry,
 *     FreeType tries to synthesize one, deriving it from other name
 *     entries.
 *
 *   style_name ::
 *     The face's style name.  This is an ASCII string, usually in English,
 *     that describes the typeface's style (like 'Italic', 'Bold',
 *     'Condensed', etc).  Not all font formats provide a style name, so
 *     this field is optional, and can be set to `NULL`.  As for
 *     `family_name`, some formats provide localized and Unicode versions
 *     of this string.  Applications should use the format-specific
 *     interface to access them.
 *
 *   num_fixed_sizes ::
 *     The number of bitmap strikes in the face.  Even if the face is
 *     scalable, there might still be bitmap strikes, which are called
 *     'sbits' in that case.
 *
 *   available_sizes ::
 *     An array of @FT_Bitmap_Size for all bitmap strikes in the face.  It
 *     is set to `NULL` if there is no bitmap strike.
 *
 *     Note that FreeType tries to sanitize the strike data since they are
 *     sometimes sloppy or incorrect, but this can easily fail.
 *
 *   num_charmaps ::
 *     The number of charmaps in the face.
 *
 *   charmaps ::
 *     An array of the charmaps of the face.
 *
 *   generic ::
 *     A field reserved for client uses.  See the @FT_Generic type
 *     description.
 *
 *   bbox ::
 *     The font bounding box.  Coordinates are expressed in font units (see
 *     `units_per_EM`).  The box is large enough to contain any glyph from
 *     the font.  Thus, `bbox.yMax` can be seen as the 'maximum ascender',
 *     and `bbox.yMin` as the 'minimum descender'.  Only relevant for
 *     scalable formats.
 *
 *     Note that the bounding box might be off by (at least) one pixel for
 *     hinted fonts.  See @FT_Size_Metrics for further discussion.
 *
 *   units_per_EM ::
 *     The number of font units per EM square for this face.  This is
 *     typically 2048 for TrueType fonts, and 1000 for Type~1 fonts.  Only
 *     relevant for scalable formats.
 *
 *   ascender ::
 *     The typographic ascender of the face, expressed in font units.  For
 *     font formats not having this information, it is set to `bbox.yMax`.
 *     Only relevant for scalable formats.
 *
 *   descender ::
 *     The typographic descender of the face, expressed in font units.  For
 *     font formats not having this information, it is set to `bbox.yMin`.
 *     Note that this field is negative for values below the baseline.
 *     Only relevant for scalable formats.
 *
 *   height ::
 *     This value is the vertical distance between two consecutive
 *     baselines, expressed in font units.  It is always positive.  Only
 *     relevant for scalable formats.
 *
 *     If you want the global glyph height, use `ascender - descender`.
 *
 *   max_advance_width ::
 *     The maximum advance width, in font units, for all glyphs in this
 *     face.  This can be used to make word wrapping computations faster.
 *     Only relevant for scalable formats.
 *
 *   max_advance_height ::
 *     The maximum advance height, in font units, for all glyphs in this
 *     face.  This is only relevant for vertical layouts, and is set to
 *     `height` for fonts that do not provide vertical metrics.  Only
 *     relevant for scalable formats.
 *
 *   underline_position ::
 *     The position, in font units, of the underline line for this face.
 *     It is the center of the underlining stem.  Only relevant for
 *     scalable formats.
 *
 *   underline_thickness ::
 *     The thickness, in font units, of the underline for this face.  Only
 *     relevant for scalable formats.
 *
 *   glyph ::
 *     The face's associated glyph slot(s).
 *
 *   size ::
 *     The current active size for this face.
 *
 *   charmap ::
 *     The current active charmap for this face.
 *
 * @note:
 *   Fields may be changed after a call to @FT_Attach_File or
 *   @FT_Attach_Stream.
 *
 *   For an OpenType variation font, the values of the following fields can
 *   change after a call to @FT_Set_Var_Design_Coordinates (and friends) if
 *   the font contains an 'MVAR' table: `ascender`, `descender`, `height`,
 *   `underline_position`, and `underline_thickness`.
 *
 *   Especially for TrueType fonts see also the documentation for
 *   @FT_Size_Metrics.
 */
typedef struct FT_FaceRec_ {
	FT_Long num_faces;
	FT_Long face_index;

	FT_Long face_flags;
	FT_Long style_flags;

	FT_Long num_glyphs;

	FT_String *family_name;
	FT_String *style_name;

	FT_Int num_fixed_sizes;
	FT_Bitmap_Size *available_sizes;

	FT_Int num_charmaps;
	FT_CharMap *charmaps;

	FT_Generic generic;

	/*# The following member variables (down to `underline_thickness`) */
	/*# are only relevant to scalable outlines; cf. @FT_Bitmap_Size    */
	/*# for bitmap fonts.                                              */
	FT_BBox bbox;

	FT_UShort units_per_EM;
	FT_Short ascender;
	FT_Short descender;
	FT_Short height;

	FT_Short max_advance_width;
	FT_Short max_advance_height;

	FT_Short underline_position;
	FT_Short underline_thickness;

	FT_GlyphSlot glyph;
	FT_Size size;
	FT_CharMap charmap;

	/*@private begin */

	FT_Driver driver;
	FT_Memory memory;
	FT_Stream stream;

	FT_ListRec sizes_list;

	FT_Generic autohint; /* face-specific auto-hinter data */
	void *extensions;    /* unused                         */

	FT_Face_Internal internal;

	/*@private end */

} FT_FaceRec;

/**************************************************************************
 *
 * @enum:
 *   FT_FACE_FLAG_XXX
 *
 * @description:
 *   A list of bit flags used in the `face_flags` field of the @FT_FaceRec
 *   structure.  They inform client applications of properties of the
 *   corresponding face.
 *
 * @values:
 *   FT_FACE_FLAG_SCALABLE ::
 *     The face contains outline glyphs.  Note that a face can contain
 *     bitmap strikes also, i.e., a face can have both this flag and
 *     @FT_FACE_FLAG_FIXED_SIZES set.
 *
 *   FT_FACE_FLAG_FIXED_SIZES ::
 *     The face contains bitmap strikes.  See also the `num_fixed_sizes`
 *     and `available_sizes` fields of @FT_FaceRec.
 *
 *   FT_FACE_FLAG_FIXED_WIDTH ::
 *     The face contains fixed-width characters (like Courier, Lucida,
 *     MonoType, etc.).
 *
 *   FT_FACE_FLAG_SFNT ::
 *     The face uses the SFNT storage scheme.  For now, this means TrueType
 *     and OpenType.
 *
 *   FT_FACE_FLAG_HORIZONTAL ::
 *     The face contains horizontal glyph metrics.  This should be set for
 *     all common formats.
 *
 *   FT_FACE_FLAG_VERTICAL ::
 *     The face contains vertical glyph metrics.  This is only available in
 *     some formats, not all of them.
 *
 *   FT_FACE_FLAG_KERNING ::
 *     The face contains kerning information.  If set, the kerning distance
 *     can be retrieved using the function @FT_Get_Kerning.  Otherwise the
 *     function always return the vector (0,0).  Note that FreeType doesn't
 *     handle kerning data from the SFNT 'GPOS' table (as present in many
 *     OpenType fonts).
 *
 *   FT_FACE_FLAG_FAST_GLYPHS ::
 *     THIS FLAG IS DEPRECATED.  DO NOT USE OR TEST IT.
 *
 *   FT_FACE_FLAG_MULTIPLE_MASTERS ::
 *     The face contains multiple masters and is capable of interpolating
 *     between them.  Supported formats are Adobe MM, TrueType GX, and
 *     OpenType variation fonts.
 *
 *     See section @multiple_masters for API details.
 *
 *   FT_FACE_FLAG_GLYPH_NAMES ::
 *     The face contains glyph names, which can be retrieved using
 *     @FT_Get_Glyph_Name.  Note that some TrueType fonts contain broken
 *     glyph name tables.  Use the function @FT_Has_PS_Glyph_Names when
 *     needed.
 *
 *   FT_FACE_FLAG_EXTERNAL_STREAM ::
 *     Used internally by FreeType to indicate that a face's stream was
 *     provided by the client application and should not be destroyed when
 *     @FT_Done_Face is called.  Don't read or test this flag.
 *
 *   FT_FACE_FLAG_HINTER ::
 *     The font driver has a hinting machine of its own.  For example, with
 *     TrueType fonts, it makes sense to use data from the SFNT 'gasp'
 *     table only if the native TrueType hinting engine (with the bytecode
 *     interpreter) is available and active.
 *
 *   FT_FACE_FLAG_CID_KEYED ::
 *     The face is CID-keyed.  In that case, the face is not accessed by
 *     glyph indices but by CID values.  For subsetted CID-keyed fonts this
 *     has the consequence that not all index values are a valid argument
 *     to @FT_Load_Glyph.  Only the CID values for which corresponding
 *     glyphs in the subsetted font exist make `FT_Load_Glyph` return
 *     successfully; in all other cases you get an
 *     `FT_Err_Invalid_Argument` error.
 *
 *     Note that CID-keyed fonts that are in an SFNT wrapper (this is, all
 *     OpenType/CFF fonts) don't have this flag set since the glyphs are
 *     accessed in the normal way (using contiguous indices); the
 *     'CID-ness' isn't visible to the application.
 *
 *   FT_FACE_FLAG_TRICKY ::
 *     The face is 'tricky', this is, it always needs the font format's
 *     native hinting engine to get a reasonable result.  A typical example
 *     is the old Chinese font `mingli.ttf` (but not `mingliu.ttc`) that
 *     uses TrueType bytecode instructions to move and scale all of its
 *     subglyphs.
 *
 *     It is not possible to auto-hint such fonts using
 *     @FT_LOAD_FORCE_AUTOHINT; it will also ignore @FT_LOAD_NO_HINTING.
 *     You have to set both @FT_LOAD_NO_HINTING and @FT_LOAD_NO_AUTOHINT to
 *     really disable hinting; however, you probably never want this except
 *     for demonstration purposes.
 *
 *     Currently, there are about a dozen TrueType fonts in the list of
 *     tricky fonts; they are hard-coded in file `ttobjs.c`.
 *
 *   FT_FACE_FLAG_COLOR ::
 *     [Since 2.5.1] The face has color glyph tables.  See @FT_LOAD_COLOR
 *     for more information.
 *
 *   FT_FACE_FLAG_VARIATION ::
 *     [Since 2.9] Set if the current face (or named instance) has been
 *     altered with @FT_Set_MM_Design_Coordinates,
 *     @FT_Set_Var_Design_Coordinates, or @FT_Set_Var_Blend_Coordinates.
 *     This flag is unset by a call to @FT_Set_Named_Instance.
 */
#define FT_FACE_FLAG_SCALABLE (1L << 0)
#define FT_FACE_FLAG_FIXED_SIZES (1L << 1)
#define FT_FACE_FLAG_FIXED_WIDTH (1L << 2)
#define FT_FACE_FLAG_SFNT (1L << 3)
#define FT_FACE_FLAG_HORIZONTAL (1L << 4)
#define FT_FACE_FLAG_VERTICAL (1L << 5)
#define FT_FACE_FLAG_KERNING (1L << 6)
#define FT_FACE_FLAG_FAST_GLYPHS (1L << 7)
#define FT_FACE_FLAG_MULTIPLE_MASTERS (1L << 8)
#define FT_FACE_FLAG_GLYPH_NAMES (1L << 9)
#define FT_FACE_FLAG_EXTERNAL_STREAM (1L << 10)
#define FT_FACE_FLAG_HINTER (1L << 11)
#define FT_FACE_FLAG_CID_KEYED (1L << 12)
#define FT_FACE_FLAG_TRICKY (1L << 13)
#define FT_FACE_FLAG_COLOR (1L << 14)
#define FT_FACE_FLAG_VARIATION (1L << 15)

/**************************************************************************
 *
 * @macro:
 *   FT_HAS_HORIZONTAL
 *
 * @description:
 *   A macro that returns true whenever a face object contains horizontal
 *   metrics (this is true for all font formats though).
 *
 * @also:
 *   @FT_HAS_VERTICAL can be used to check for vertical metrics.
 *
 */
#define FT_HAS_HORIZONTAL(face) ((face)->face_flags & FT_FACE_FLAG_HORIZONTAL)

/**************************************************************************
 *
 * @macro:
 *   FT_HAS_VERTICAL
 *
 * @description:
 *   A macro that returns true whenever a face object contains real
 *   vertical metrics (and not only synthesized ones).
 *
 */
#define FT_HAS_VERTICAL(face) ((face)->face_flags & FT_FACE_FLAG_VERTICAL)

/**************************************************************************
 *
 * @macro:
 *   FT_HAS_KERNING
 *
 * @description:
 *   A macro that returns true whenever a face object contains kerning data
 *   that can be accessed with @FT_Get_Kerning.
 *
 */
#define FT_HAS_KERNING(face) ((face)->face_flags & FT_FACE_FLAG_KERNING)

/**************************************************************************
 *
 * @macro:
 *   FT_IS_SCALABLE
 *
 * @description:
 *   A macro that returns true whenever a face object contains a scalable
 *   font face (true for TrueType, Type~1, Type~42, CID, OpenType/CFF, and
 *   PFR font formats).
 *
 */
#define FT_IS_SCALABLE(face) ((face)->face_flags & FT_FACE_FLAG_SCALABLE)

/**************************************************************************
 *
 * @macro:
 *   FT_IS_SFNT
 *
 * @description:
 *   A macro that returns true whenever a face object contains a font whose
 *   format is based on the SFNT storage scheme.  This usually means:
 *   TrueType fonts, OpenType fonts, as well as SFNT-based embedded bitmap
 *   fonts.
 *
 *   If this macro is true, all functions defined in @FT_SFNT_NAMES_H and
 *   @FT_TRUETYPE_TABLES_H are available.
 *
 */
#define FT_IS_SFNT(face) ((face)->face_flags & FT_FACE_FLAG_SFNT)

/**************************************************************************
 *
 * @macro:
 *   FT_IS_FIXED_WIDTH
 *
 * @description:
 *   A macro that returns true whenever a face object contains a font face
 *   that contains fixed-width (or 'monospace', 'fixed-pitch', etc.)
 *   glyphs.
 *
 */
#define FT_IS_FIXED_WIDTH(face) ((face)->face_flags & FT_FACE_FLAG_FIXED_WIDTH)

/**************************************************************************
 *
 * @macro:
 *   FT_HAS_FIXED_SIZES
 *
 * @description:
 *   A macro that returns true whenever a face object contains some
 *   embedded bitmaps.  See the `available_sizes` field of the @FT_FaceRec
 *   structure.
 *
 */
#define FT_HAS_FIXED_SIZES(face) ((face)->face_flags & FT_FACE_FLAG_FIXED_SIZES)

/**************************************************************************
 *
 * @macro:
 *   FT_HAS_FAST_GLYPHS
 *
 * @description:
 *   Deprecated.
 *
 */
#define FT_HAS_FAST_GLYPHS(face) 0

/**************************************************************************
 *
 * @macro:
 *   FT_HAS_GLYPH_NAMES
 *
 * @description:
 *   A macro that returns true whenever a face object contains some glyph
 *   names that can be accessed through @FT_Get_Glyph_Name.
 *
 */
#define FT_HAS_GLYPH_NAMES(face) ((face)->face_flags & FT_FACE_FLAG_GLYPH_NAMES)

/**************************************************************************
 *
 * @macro:
 *   FT_HAS_MULTIPLE_MASTERS
 *
 * @description:
 *   A macro that returns true whenever a face object contains some
 *   multiple masters.  The functions provided by @FT_MULTIPLE_MASTERS_H
 *   are then available to choose the exact design you want.
 *
 */
#define FT_HAS_MULTIPLE_MASTERS(face) ((face)->face_flags & FT_FACE_FLAG_MULTIPLE_MASTERS)

/**************************************************************************
 *
 * @macro:
 *   FT_IS_NAMED_INSTANCE
 *
 * @description:
 *   A macro that returns true whenever a face object is a named instance
 *   of a GX or OpenType variation font.
 *
 *   [Since 2.9] Changing the design coordinates with
 *   @FT_Set_Var_Design_Coordinates or @FT_Set_Var_Blend_Coordinates does
 *   not influence the return value of this macro (only
 *   @FT_Set_Named_Instance does that).
 *
 * @since:
 *   2.7
 *
 */
#define FT_IS_NAMED_INSTANCE(face) ((face)->face_index & 0x7FFF0000L)

/**************************************************************************
 *
 * @macro:
 *   FT_IS_VARIATION
 *
 * @description:
 *   A macro that returns true whenever a face object has been altered by
 *   @FT_Set_MM_Design_Coordinates, @FT_Set_Var_Design_Coordinates, or
 *   @FT_Set_Var_Blend_Coordinates.
 *
 * @since:
 *   2.9
 *
 */
#define FT_IS_VARIATION(face) ((face)->face_flags & FT_FACE_FLAG_VARIATION)

/**************************************************************************
 *
 * @macro:
 *   FT_IS_CID_KEYED
 *
 * @description:
 *   A macro that returns true whenever a face object contains a CID-keyed
 *   font.  See the discussion of @FT_FACE_FLAG_CID_KEYED for more details.
 *
 *   If this macro is true, all functions defined in @FT_CID_H are
 *   available.
 *
 */
#define FT_IS_CID_KEYED(face) ((face)->face_flags & FT_FACE_FLAG_CID_KEYED)

/**************************************************************************
 *
 * @macro:
 *   FT_IS_TRICKY
 *
 * @description:
 *   A macro that returns true whenever a face represents a 'tricky' font.
 *   See the discussion of @FT_FACE_FLAG_TRICKY for more details.
 *
 */
#define FT_IS_TRICKY(face) ((face)->face_flags & FT_FACE_FLAG_TRICKY)

/**************************************************************************
 *
 * @macro:
 *   FT_HAS_COLOR
 *
 * @description:
 *   A macro that returns true whenever a face object contains tables for
 *   color glyphs.
 *
 * @since:
 *   2.5.1
 *
 */
#define FT_HAS_COLOR(face) ((face)->face_flags & FT_FACE_FLAG_COLOR)

/**************************************************************************
 *
 * @enum:
 *   FT_STYLE_FLAG_XXX
 *
 * @description:
 *   A list of bit flags to indicate the style of a given face.  These are
 *   used in the `style_flags` field of @FT_FaceRec.
 *
 * @values:
 *   FT_STYLE_FLAG_ITALIC ::
 *     The face style is italic or oblique.
 *
 *   FT_STYLE_FLAG_BOLD ::
 *     The face is bold.
 *
 * @note:
 *   The style information as provided by FreeType is very basic.  More
 *   details are beyond the scope and should be done on a higher level (for
 *   example, by analyzing various fields of the 'OS/2' table in SFNT based
 *   fonts).
 */
#define FT_STYLE_FLAG_ITALIC (1 << 0)
#define FT_STYLE_FLAG_BOLD (1 << 1)

/**************************************************************************
 *
 * @type:
 *   FT_Size_Internal
 *
 * @description:
 *   An opaque handle to an `FT_Size_InternalRec` structure, used to model
 *   private data of a given @FT_Size object.
 */
typedef struct FT_Size_InternalRec_ *FT_Size_Internal;

/**************************************************************************
 *
 * @struct:
 *   FT_Size_Metrics
 *
 * @description:
 *   The size metrics structure gives the metrics of a size object.
 *
 * @fields:
 *   x_ppem ::
 *     The width of the scaled EM square in pixels, hence the term 'ppem'
 *     (pixels per EM).  It is also referred to as 'nominal width'.
 *
 *   y_ppem ::
 *     The height of the scaled EM square in pixels, hence the term 'ppem'
 *     (pixels per EM).  It is also referred to as 'nominal height'.
 *
 *   x_scale ::
 *     A 16.16 fractional scaling value to convert horizontal metrics from
 *     font units to 26.6 fractional pixels.  Only relevant for scalable
 *     font formats.
 *
 *   y_scale ::
 *     A 16.16 fractional scaling value to convert vertical metrics from
 *     font units to 26.6 fractional pixels.  Only relevant for scalable
 *     font formats.
 *
 *   ascender ::
 *     The ascender in 26.6 fractional pixels, rounded up to an integer
 *     value.  See @FT_FaceRec for the details.
 *
 *   descender ::
 *     The descender in 26.6 fractional pixels, rounded down to an integer
 *     value.  See @FT_FaceRec for the details.
 *
 *   height ::
 *     The height in 26.6 fractional pixels, rounded to an integer value.
 *     See @FT_FaceRec for the details.
 *
 *   max_advance ::
 *     The maximum advance width in 26.6 fractional pixels, rounded to an
 *     integer value.  See @FT_FaceRec for the details.
 *
 * @note:
 *   The scaling values, if relevant, are determined first during a size
 *   changing operation.  The remaining fields are then set by the driver.
 *   For scalable formats, they are usually set to scaled values of the
 *   corresponding fields in @FT_FaceRec.  Some values like ascender or
 *   descender are rounded for historical reasons; more precise values (for
 *   outline fonts) can be derived by scaling the corresponding @FT_FaceRec
 *   values manually, with code similar to the following.
 *
 *   ```
 *     scaled_ascender = FT_MulFix( face->ascender,
 *                                  size_metrics->y_scale );
 *   ```
 *
 *   Note that due to glyph hinting and the selected rendering mode these
 *   values are usually not exact; consequently, they must be treated as
 *   unreliable with an error margin of at least one pixel!
 *
 *   Indeed, the only way to get the exact metrics is to render _all_
 *   glyphs.  As this would be a definite performance hit, it is up to
 *   client applications to perform such computations.
 *
 *   The `FT_Size_Metrics` structure is valid for bitmap fonts also.
 *
 *
 *   **TrueType fonts with native bytecode hinting**
 *
 *   All applications that handle TrueType fonts with native hinting must
 *   be aware that TTFs expect different rounding of vertical font
 *   dimensions.  The application has to cater for this, especially if it
 *   wants to rely on a TTF's vertical data (for example, to properly align
 *   box characters vertically).
 *
 *   Only the application knows _in advance_ that it is going to use native
 *   hinting for TTFs!  FreeType, on the other hand, selects the hinting
 *   mode not at the time of creating an @FT_Size object but much later,
 *   namely while calling @FT_Load_Glyph.
 *
 *   Here is some pseudo code that illustrates a possible solution.
 *
 *   ```
 *     font_format = FT_Get_Font_Format( face );
 *
 *     if ( !strcmp( font_format, "TrueType" ) &&
 *          do_native_bytecode_hinting         )
 *     {
 *       ascender  = ROUND( FT_MulFix( face->ascender,
 *                                     size_metrics->y_scale ) );
 *       descender = ROUND( FT_MulFix( face->descender,
 *                                     size_metrics->y_scale ) );
 *     }
 *     else
 *     {
 *       ascender  = size_metrics->ascender;
 *       descender = size_metrics->descender;
 *     }
 *
 *     height      = size_metrics->height;
 *     max_advance = size_metrics->max_advance;
 *   ```
 */
typedef struct FT_Size_Metrics_ {
	FT_UShort x_ppem; /* horizontal pixels per EM               */
	FT_UShort y_ppem; /* vertical pixels per EM                 */

	FT_Fixed x_scale; /* scaling values used to convert font    */
	FT_Fixed y_scale; /* units to 26.6 fractional pixels        */

	FT_Pos ascender;    /* ascender in 26.6 frac. pixels          */
	FT_Pos descender;   /* descender in 26.6 frac. pixels         */
	FT_Pos height;      /* text height in 26.6 frac. pixels       */
	FT_Pos max_advance; /* max horizontal advance, in 26.6 pixels */

} FT_Size_Metrics;

/**************************************************************************
 *
 * @struct:
 *   FT_SizeRec
 *
 * @description:
 *   FreeType root size class structure.  A size object models a face
 *   object at a given size.
 *
 * @fields:
 *   face ::
 *     Handle to the parent face object.
 *
 *   generic ::
 *     A typeless pointer, unused by the FreeType library or any of its
 *     drivers.  It can be used by client applications to link their own
 *     data to each size object.
 *
 *   metrics ::
 *     Metrics for this size object.  This field is read-only.
 */
typedef struct FT_SizeRec_ {
	FT_Face face;            /* parent face object              */
	FT_Generic generic;      /* generic pointer for client uses */
	FT_Size_Metrics metrics; /* size metrics                    */
	FT_Size_Internal internal;

} FT_SizeRec;

/**************************************************************************
 *
 * @struct:
 *   FT_SubGlyph
 *
 * @description:
 *   The subglyph structure is an internal object used to describe
 *   subglyphs (for example, in the case of composites).
 *
 * @note:
 *   The subglyph implementation is not part of the high-level API, hence
 *   the forward structure declaration.
 *
 *   You can however retrieve subglyph information with
 *   @FT_Get_SubGlyph_Info.
 */
typedef struct FT_SubGlyphRec_ *FT_SubGlyph;

/**************************************************************************
 *
 * @type:
 *   FT_Slot_Internal
 *
 * @description:
 *   An opaque handle to an `FT_Slot_InternalRec` structure, used to model
 *   private data of a given @FT_GlyphSlot object.
 */
typedef struct FT_Slot_InternalRec_ *FT_Slot_Internal;

/**************************************************************************
 *
 * @struct:
 *   FT_GlyphSlotRec
 *
 * @description:
 *   FreeType root glyph slot class structure.  A glyph slot is a container
 *   where individual glyphs can be loaded, be they in outline or bitmap
 *   format.
 *
 * @fields:
 *   library ::
 *     A handle to the FreeType library instance this slot belongs to.
 *
 *   face ::
 *     A handle to the parent face object.
 *
 *   next ::
 *     In some cases (like some font tools), several glyph slots per face
 *     object can be a good thing.  As this is rare, the glyph slots are
 *     listed through a direct, single-linked list using its `next` field.
 *
 *   glyph_index ::
 *     [Since 2.10] The glyph index passed as an argument to @FT_Load_Glyph
 *     while initializing the glyph slot.
 *
 *   generic ::
 *     A typeless pointer unused by the FreeType library or any of its
 *     drivers.  It can be used by client applications to link their own
 *     data to each glyph slot object.
 *
 *   metrics ::
 *     The metrics of the last loaded glyph in the slot.  The returned
 *     values depend on the last load flags (see the @FT_Load_Glyph API
 *     function) and can be expressed either in 26.6 fractional pixels or
 *     font units.
 *
 *     Note that even when the glyph image is transformed, the metrics are
 *     not.
 *
 *   linearHoriAdvance ::
 *     The advance width of the unhinted glyph.  Its value is expressed in
 *     16.16 fractional pixels, unless @FT_LOAD_LINEAR_DESIGN is set when
 *     loading the glyph.  This field can be important to perform correct
 *     WYSIWYG layout.  Only relevant for outline glyphs.
 *
 *   linearVertAdvance ::
 *     The advance height of the unhinted glyph.  Its value is expressed in
 *     16.16 fractional pixels, unless @FT_LOAD_LINEAR_DESIGN is set when
 *     loading the glyph.  This field can be important to perform correct
 *     WYSIWYG layout.  Only relevant for outline glyphs.
 *
 *   advance ::
 *     This shorthand is, depending on @FT_LOAD_IGNORE_TRANSFORM, the
 *     transformed (hinted) advance width for the glyph, in 26.6 fractional
 *     pixel format.  As specified with @FT_LOAD_VERTICAL_LAYOUT, it uses
 *     either the `horiAdvance` or the `vertAdvance` value of `metrics`
 *     field.
 *
 *   format ::
 *     This field indicates the format of the image contained in the glyph
 *     slot.  Typically @FT_GLYPH_FORMAT_BITMAP, @FT_GLYPH_FORMAT_OUTLINE,
 *     or @FT_GLYPH_FORMAT_COMPOSITE, but other values are possible.
 *
 *   bitmap ::
 *     This field is used as a bitmap descriptor.  Note that the address
 *     and content of the bitmap buffer can change between calls of
 *     @FT_Load_Glyph and a few other functions.
 *
 *   bitmap_left ::
 *     The bitmap's left bearing expressed in integer pixels.
 *
 *   bitmap_top ::
 *     The bitmap's top bearing expressed in integer pixels.  This is the
 *     distance from the baseline to the top-most glyph scanline, upwards
 *     y~coordinates being **positive**.
 *
 *   outline ::
 *     The outline descriptor for the current glyph image if its format is
 *     @FT_GLYPH_FORMAT_OUTLINE.  Once a glyph is loaded, `outline` can be
 *     transformed, distorted, emboldened, etc.  However, it must not be
 *     freed.
 *
 *     [Since 2.10.1] If @FT_LOAD_NO_SCALE is set, outline coordinates of
 *     OpenType variation fonts for a selected instance are internally
 *     handled as 26.6 fractional font units but returned as (rounded)
 *     integers, as expected.  To get unrounded font units, don't use
 *     @FT_LOAD_NO_SCALE but load the glyph with @FT_LOAD_NO_HINTING and
 *     scale it, using the font's `units_per_EM` value as the ppem.
 *
 *   num_subglyphs ::
 *     The number of subglyphs in a composite glyph.  This field is only
 *     valid for the composite glyph format that should normally only be
 *     loaded with the @FT_LOAD_NO_RECURSE flag.
 *
 *   subglyphs ::
 *     An array of subglyph descriptors for composite glyphs.  There are
 *     `num_subglyphs` elements in there.  Currently internal to FreeType.
 *
 *   control_data ::
 *     Certain font drivers can also return the control data for a given
 *     glyph image (e.g.  TrueType bytecode, Type~1 charstrings, etc.).
 *     This field is a pointer to such data; it is currently internal to
 *     FreeType.
 *
 *   control_len ::
 *     This is the length in bytes of the control data.  Currently internal
 *     to FreeType.
 *
 *   other ::
 *     Reserved.
 *
 *   lsb_delta ::
 *     The difference between hinted and unhinted left side bearing while
 *     auto-hinting is active.  Zero otherwise.
 *
 *   rsb_delta ::
 *     The difference between hinted and unhinted right side bearing while
 *     auto-hinting is active.  Zero otherwise.
 *
 * @note:
 *   If @FT_Load_Glyph is called with default flags (see @FT_LOAD_DEFAULT)
 *   the glyph image is loaded in the glyph slot in its native format
 *   (e.g., an outline glyph for TrueType and Type~1 formats).  [Since 2.9]
 *   The prospective bitmap metrics are calculated according to
 *   @FT_LOAD_TARGET_XXX and other flags even for the outline glyph, even
 *   if @FT_LOAD_RENDER is not set.
 *
 *   This image can later be converted into a bitmap by calling
 *   @FT_Render_Glyph.  This function searches the current renderer for the
 *   native image's format, then invokes it.
 *
 *   The renderer is in charge of transforming the native image through the
 *   slot's face transformation fields, then converting it into a bitmap
 *   that is returned in `slot->bitmap`.
 *
 *   Note that `slot->bitmap_left` and `slot->bitmap_top` are also used to
 *   specify the position of the bitmap relative to the current pen
 *   position (e.g., coordinates (0,0) on the baseline).  Of course,
 *   `slot->format` is also changed to @FT_GLYPH_FORMAT_BITMAP.
 *
 *   Here is a small pseudo code fragment that shows how to use `lsb_delta`
 *   and `rsb_delta` to do fractional positioning of glyphs:
 *
 *   ```
 *     FT_GlyphSlot  slot     = face->glyph;
 *     FT_Pos        origin_x = 0;
 *
 *
 *     for all glyphs do
 *       <load glyph with `FT_Load_Glyph'>
 *
 *       FT_Outline_Translate( slot->outline, origin_x & 63, 0 );
 *
 *       <save glyph image, or render glyph, or ...>
 *
 *       <compute kern between current and next glyph
 *        and add it to `origin_x'>
 *
 *       origin_x += slot->advance.x;
 *       origin_x += slot->lsb_delta - slot->rsb_delta;
 *     endfor
 *   ```
 *
 *   Here is another small pseudo code fragment that shows how to use
 *   `lsb_delta` and `rsb_delta` to improve integer positioning of glyphs:
 *
 *   ```
 *     FT_GlyphSlot  slot           = face->glyph;
 *     FT_Pos        origin_x       = 0;
 *     FT_Pos        prev_rsb_delta = 0;
 *
 *
 *     for all glyphs do
 *       <compute kern between current and previous glyph
 *        and add it to `origin_x'>
 *
 *       <load glyph with `FT_Load_Glyph'>
 *
 *       if ( prev_rsb_delta - slot->lsb_delta >  32 )
 *         origin_x -= 64;
 *       else if ( prev_rsb_delta - slot->lsb_delta < -31 )
 *         origin_x += 64;
 *
 *       prev_rsb_delta = slot->rsb_delta;
 *
 *       <save glyph image, or render glyph, or ...>
 *
 *       origin_x += slot->advance.x;
 *     endfor
 *   ```
 *
 *   If you use strong auto-hinting, you **must** apply these delta values!
 *   Otherwise you will experience far too large inter-glyph spacing at
 *   small rendering sizes in most cases.  Note that it doesn't harm to use
 *   the above code for other hinting modes also, since the delta values
 *   are zero then.
 */
typedef struct FT_GlyphSlotRec_ {
	FT_Library library;
	FT_Face face;
	FT_GlyphSlot next;
	FT_UInt glyph_index; /* new in 2.10; was reserved previously */
	FT_Generic generic;

	FT_Glyph_Metrics metrics;
	FT_Fixed linearHoriAdvance;
	FT_Fixed linearVertAdvance;
	FT_Vector advance;

	FT_Glyph_Format format;

	FT_Bitmap bitmap;
	FT_Int bitmap_left;
	FT_Int bitmap_top;

	FT_Outline outline;

	FT_UInt num_subglyphs;
	FT_SubGlyph subglyphs;

	void *control_data;
	long control_len;

	FT_Pos lsb_delta;
	FT_Pos rsb_delta;

	void *other;

	FT_Slot_Internal internal;

} FT_GlyphSlotRec;

/*************************************************************************/
/*************************************************************************/
/*                                                                       */
/*                         F U N C T I O N S                             */
/*                                                                       */
/*************************************************************************/
/*************************************************************************/

/**************************************************************************
 *
 * @function:
 *   FT_Init_FreeType
 *
 * @description:
 *   Initialize a new FreeType library object.  The set of modules that are
 *   registered by this function is determined at build time.
 *
 * @output:
 *   alibrary ::
 *     A handle to a new library object.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   In case you want to provide your own memory allocating routines, use
 *   @FT_New_Library instead, followed by a call to @FT_Add_Default_Modules
 *   (or a series of calls to @FT_Add_Module) and
 *   @FT_Set_Default_Properties.
 *
 *   See the documentation of @FT_Library and @FT_Face for multi-threading
 *   issues.
 *
 *   If you need reference-counting (cf. @FT_Reference_Library), use
 *   @FT_New_Library and @FT_Done_Library.
 *
 *   If compilation option `FT_CONFIG_OPTION_ENVIRONMENT_PROPERTIES` is
 *   set, this function reads the `FREETYPE_PROPERTIES` environment
 *   variable to control driver properties.  See section @properties for
 *   more.
 */
FT_EXPORT(FT_Error)
FT_Init_FreeType(FT_Library *alibrary);

/**************************************************************************
 *
 * @function:
 *   FT_Done_FreeType
 *
 * @description:
 *   Destroy a given FreeType library object and all of its children,
 *   including resources, drivers, faces, sizes, etc.
 *
 * @input:
 *   library ::
 *     A handle to the target library object.
 *
 * @return:
 *   FreeType error code.  0~means success.
 */
FT_EXPORT(FT_Error)
FT_Done_FreeType(FT_Library library);

/**************************************************************************
 *
 * @enum:
 *   FT_OPEN_XXX
 *
 * @description:
 *   A list of bit field constants used within the `flags` field of the
 *   @FT_Open_Args structure.
 *
 * @values:
 *   FT_OPEN_MEMORY ::
 *     This is a memory-based stream.
 *
 *   FT_OPEN_STREAM ::
 *     Copy the stream from the `stream` field.
 *
 *   FT_OPEN_PATHNAME ::
 *     Create a new input stream from a C~path name.
 *
 *   FT_OPEN_DRIVER ::
 *     Use the `driver` field.
 *
 *   FT_OPEN_PARAMS ::
 *     Use the `num_params` and `params` fields.
 *
 * @note:
 *   The `FT_OPEN_MEMORY`, `FT_OPEN_STREAM`, and `FT_OPEN_PATHNAME` flags
 *   are mutually exclusive.
 */
#define FT_OPEN_MEMORY 0x1
#define FT_OPEN_STREAM 0x2
#define FT_OPEN_PATHNAME 0x4
#define FT_OPEN_DRIVER 0x8
#define FT_OPEN_PARAMS 0x10

/* these constants are deprecated; use the corresponding `FT_OPEN_XXX` */
/* values instead                                                      */
#define ft_open_memory FT_OPEN_MEMORY
#define ft_open_stream FT_OPEN_STREAM
#define ft_open_pathname FT_OPEN_PATHNAME
#define ft_open_driver FT_OPEN_DRIVER
#define ft_open_params FT_OPEN_PARAMS

/**************************************************************************
 *
 * @struct:
 *   FT_Parameter
 *
 * @description:
 *   A simple structure to pass more or less generic parameters to
 *   @FT_Open_Face and @FT_Face_Properties.
 *
 * @fields:
 *   tag ::
 *     A four-byte identification tag.
 *
 *   data ::
 *     A pointer to the parameter data.
 *
 * @note:
 *   The ID and function of parameters are driver-specific.  See section
 *   @parameter_tags for more information.
 */
typedef struct FT_Parameter_ {
	FT_ULong tag;
	FT_Pointer data;

} FT_Parameter;

/**************************************************************************
 *
 * @struct:
 *   FT_Open_Args
 *
 * @description:
 *   A structure to indicate how to open a new font file or stream.  A
 *   pointer to such a structure can be used as a parameter for the
 *   functions @FT_Open_Face and @FT_Attach_Stream.
 *
 * @fields:
 *   flags ::
 *     A set of bit flags indicating how to use the structure.
 *
 *   memory_base ::
 *     The first byte of the file in memory.
 *
 *   memory_size ::
 *     The size in bytes of the file in memory.
 *
 *   pathname ::
 *     A pointer to an 8-bit file pathname.
 *
 *   stream ::
 *     A handle to a source stream object.
 *
 *   driver ::
 *     This field is exclusively used by @FT_Open_Face; it simply specifies
 *     the font driver to use for opening the face.  If set to `NULL`,
 *     FreeType tries to load the face with each one of the drivers in its
 *     list.
 *
 *   num_params ::
 *     The number of extra parameters.
 *
 *   params ::
 *     Extra parameters passed to the font driver when opening a new face.
 *
 * @note:
 *   The stream type is determined by the contents of `flags` that are
 *   tested in the following order by @FT_Open_Face:
 *
 *   If the @FT_OPEN_MEMORY bit is set, assume that this is a memory file
 *   of `memory_size` bytes, located at `memory_address`.  The data are not
 *   copied, and the client is responsible for releasing and destroying
 *   them _after_ the corresponding call to @FT_Done_Face.
 *
 *   Otherwise, if the @FT_OPEN_STREAM bit is set, assume that a custom
 *   input stream `stream` is used.
 *
 *   Otherwise, if the @FT_OPEN_PATHNAME bit is set, assume that this is a
 *   normal file and use `pathname` to open it.
 *
 *   If the @FT_OPEN_DRIVER bit is set, @FT_Open_Face only tries to open
 *   the file with the driver whose handler is in `driver`.
 *
 *   If the @FT_OPEN_PARAMS bit is set, the parameters given by
 *   `num_params` and `params` is used.  They are ignored otherwise.
 *
 *   Ideally, both the `pathname` and `params` fields should be tagged as
 *   'const'; this is missing for API backward compatibility.  In other
 *   words, applications should treat them as read-only.
 */
typedef struct FT_Open_Args_ {
	FT_UInt flags;
	const FT_Byte *memory_base;
	FT_Long memory_size;
	FT_String *pathname;
	FT_Stream stream;
	FT_Module driver;
	FT_Int num_params;
	FT_Parameter *params;

} FT_Open_Args;

/**************************************************************************
 *
 * @function:
 *   FT_New_Face
 *
 * @description:
 *   Call @FT_Open_Face to open a font by its pathname.
 *
 * @inout:
 *   library ::
 *     A handle to the library resource.
 *
 * @input:
 *   pathname ::
 *     A path to the font file.
 *
 *   face_index ::
 *     See @FT_Open_Face for a detailed description of this parameter.
 *
 * @output:
 *   aface ::
 *     A handle to a new face object.  If `face_index` is greater than or
 *     equal to zero, it must be non-`NULL`.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   Use @FT_Done_Face to destroy the created @FT_Face object (along with
 *   its slot and sizes).
 */
FT_EXPORT(FT_Error)
FT_New_Face(FT_Library library, const char *filepathname, FT_Long face_index, FT_Face *aface);

/**************************************************************************
 *
 * @function:
 *   FT_New_Memory_Face
 *
 * @description:
 *   Call @FT_Open_Face to open a font that has been loaded into memory.
 *
 * @inout:
 *   library ::
 *     A handle to the library resource.
 *
 * @input:
 *   file_base ::
 *     A pointer to the beginning of the font data.
 *
 *   file_size ::
 *     The size of the memory chunk used by the font data.
 *
 *   face_index ::
 *     See @FT_Open_Face for a detailed description of this parameter.
 *
 * @output:
 *   aface ::
 *     A handle to a new face object.  If `face_index` is greater than or
 *     equal to zero, it must be non-`NULL`.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   You must not deallocate the memory before calling @FT_Done_Face.
 */
FT_EXPORT(FT_Error)
FT_New_Memory_Face(FT_Library library, const FT_Byte *file_base, FT_Long file_size,
                   FT_Long face_index, FT_Face *aface);

/**************************************************************************
 *
 * @function:
 *   FT_Open_Face
 *
 * @description:
 *   Create a face object from a given resource described by @FT_Open_Args.
 *
 * @inout:
 *   library ::
 *     A handle to the library resource.
 *
 * @input:
 *   args ::
 *     A pointer to an `FT_Open_Args` structure that must be filled by the
 *     caller.
 *
 *   face_index ::
 *     This field holds two different values.  Bits 0-15 are the index of
 *     the face in the font file (starting with value~0).  Set it to~0 if
 *     there is only one face in the font file.
 *
 *     [Since 2.6.1] Bits 16-30 are relevant to GX and OpenType variation
 *     fonts only, specifying the named instance index for the current face
 *     index (starting with value~1; value~0 makes FreeType ignore named
 *     instances).  For non-variation fonts, bits 16-30 are ignored.
 *     Assuming that you want to access the third named instance in face~4,
 *     `face_index` should be set to 0x00030004.  If you want to access
 *     face~4 without variation handling, simply set `face_index` to
 *     value~4.
 *
 *     `FT_Open_Face` and its siblings can be used to quickly check whether
 *     the font format of a given font resource is supported by FreeType.
 *     In general, if the `face_index` argument is negative, the function's
 *     return value is~0 if the font format is recognized, or non-zero
 *     otherwise.  The function allocates a more or less empty face handle
 *     in `*aface` (if `aface` isn't `NULL`); the only two useful fields in
 *     this special case are `face->num_faces` and `face->style_flags`.
 *     For any negative value of `face_index`, `face->num_faces` gives the
 *     number of faces within the font file.  For the negative value
 *     '-(N+1)' (with 'N' a non-negative 16-bit value), bits 16-30 in
 *     `face->style_flags` give the number of named instances in face 'N'
 *     if we have a variation font (or zero otherwise).  After examination,
 *     the returned @FT_Face structure should be deallocated with a call to
 *     @FT_Done_Face.
 *
 * @output:
 *   aface ::
 *     A handle to a new face object.  If `face_index` is greater than or
 *     equal to zero, it must be non-`NULL`.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   Unlike FreeType 1.x, this function automatically creates a glyph slot
 *   for the face object that can be accessed directly through
 *   `face->glyph`.
 *
 *   Each new face object created with this function also owns a default
 *   @FT_Size object, accessible as `face->size`.
 *
 *   One @FT_Library instance can have multiple face objects, this is,
 *   @FT_Open_Face and its siblings can be called multiple times using the
 *   same `library` argument.
 *
 *   See the discussion of reference counters in the description of
 *   @FT_Reference_Face.
 *
 * @example:
 *   To loop over all faces, use code similar to the following snippet
 *   (omitting the error handling).
 *
 *   ```
 *     ...
 *     FT_Face  face;
 *     FT_Long  i, num_faces;
 *
 *
 *     error = FT_Open_Face( library, args, -1, &face );
 *     if ( error ) { ... }
 *
 *     num_faces = face->num_faces;
 *     FT_Done_Face( face );
 *
 *     for ( i = 0; i < num_faces; i++ )
 *     {
 *       ...
 *       error = FT_Open_Face( library, args, i, &face );
 *       ...
 *       FT_Done_Face( face );
 *       ...
 *     }
 *   ```
 *
 *   To loop over all valid values for `face_index`, use something similar
 *   to the following snippet, again without error handling.  The code
 *   accesses all faces immediately (thus only a single call of
 *   `FT_Open_Face` within the do-loop), with and without named instances.
 *
 *   ```
 *     ...
 *     FT_Face  face;
 *
 *     FT_Long  num_faces     = 0;
 *     FT_Long  num_instances = 0;
 *
 *     FT_Long  face_idx     = 0;
 *     FT_Long  instance_idx = 0;
 *
 *
 *     do
 *     {
 *       FT_Long  id = ( instance_idx << 16 ) + face_idx;
 *
 *
 *       error = FT_Open_Face( library, args, id, &face );
 *       if ( error ) { ... }
 *
 *       num_faces     = face->num_faces;
 *       num_instances = face->style_flags >> 16;
 *
 *       ...
 *
 *       FT_Done_Face( face );
 *
 *       if ( instance_idx < num_instances )
 *         instance_idx++;
 *       else
 *       {
 *         face_idx++;
 *         instance_idx = 0;
 *       }
 *
 *     } while ( face_idx < num_faces )
 *   ```
 */
FT_EXPORT(FT_Error)
FT_Open_Face(FT_Library library, const FT_Open_Args *args, FT_Long face_index, FT_Face *aface);

/**************************************************************************
 *
 * @function:
 *   FT_Attach_File
 *
 * @description:
 *   Call @FT_Attach_Stream to attach a file.
 *
 * @inout:
 *   face ::
 *     The target face object.
 *
 * @input:
 *   filepathname ::
 *     The pathname.
 *
 * @return:
 *   FreeType error code.  0~means success.
 */
FT_EXPORT(FT_Error)
FT_Attach_File(FT_Face face, const char *filepathname);

/**************************************************************************
 *
 * @function:
 *   FT_Attach_Stream
 *
 * @description:
 *   'Attach' data to a face object.  Normally, this is used to read
 *   additional information for the face object.  For example, you can
 *   attach an AFM file that comes with a Type~1 font to get the kerning
 *   values and other metrics.
 *
 * @inout:
 *   face ::
 *     The target face object.
 *
 * @input:
 *   parameters ::
 *     A pointer to @FT_Open_Args that must be filled by the caller.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   The meaning of the 'attach' (i.e., what really happens when the new
 *   file is read) is not fixed by FreeType itself.  It really depends on
 *   the font format (and thus the font driver).
 *
 *   Client applications are expected to know what they are doing when
 *   invoking this function.  Most drivers simply do not implement file or
 *   stream attachments.
 */
FT_EXPORT(FT_Error)
FT_Attach_Stream(FT_Face face, FT_Open_Args *parameters);

/**************************************************************************
 *
 * @function:
 *   FT_Reference_Face
 *
 * @description:
 *   A counter gets initialized to~1 at the time an @FT_Face structure is
 *   created.  This function increments the counter.  @FT_Done_Face then
 *   only destroys a face if the counter is~1, otherwise it simply
 *   decrements the counter.
 *
 *   This function helps in managing life-cycles of structures that
 *   reference @FT_Face objects.
 *
 * @input:
 *   face ::
 *     A handle to a target face object.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @since:
 *   2.4.2
 */
FT_EXPORT(FT_Error)
FT_Reference_Face(FT_Face face);

/**************************************************************************
 *
 * @function:
 *   FT_Done_Face
 *
 * @description:
 *   Discard a given face object, as well as all of its child slots and
 *   sizes.
 *
 * @input:
 *   face ::
 *     A handle to a target face object.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   See the discussion of reference counters in the description of
 *   @FT_Reference_Face.
 */
FT_EXPORT(FT_Error)
FT_Done_Face(FT_Face face);

/**************************************************************************
 *
 * @function:
 *   FT_Select_Size
 *
 * @description:
 *   Select a bitmap strike.  To be more precise, this function sets the
 *   scaling factors of the active @FT_Size object in a face so that
 *   bitmaps from this particular strike are taken by @FT_Load_Glyph and
 *   friends.
 *
 * @inout:
 *   face ::
 *     A handle to a target face object.
 *
 * @input:
 *   strike_index ::
 *     The index of the bitmap strike in the `available_sizes` field of
 *     @FT_FaceRec structure.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   For bitmaps embedded in outline fonts it is common that only a subset
 *   of the available glyphs at a given ppem value is available.  FreeType
 *   silently uses outlines if there is no bitmap for a given glyph index.
 *
 *   For GX and OpenType variation fonts, a bitmap strike makes sense only
 *   if the default instance is active (this is, no glyph variation takes
 *   place); otherwise, FreeType simply ignores bitmap strikes.  The same
 *   is true for all named instances that are different from the default
 *   instance.
 *
 *   Don't use this function if you are using the FreeType cache API.
 */
FT_EXPORT(FT_Error)
FT_Select_Size(FT_Face face, FT_Int strike_index);

/**************************************************************************
 *
 * @enum:
 *   FT_Size_Request_Type
 *
 * @description:
 *   An enumeration type that lists the supported size request types, i.e.,
 *   what input size (in font units) maps to the requested output size (in
 *   pixels, as computed from the arguments of @FT_Size_Request).
 *
 * @values:
 *   FT_SIZE_REQUEST_TYPE_NOMINAL ::
 *     The nominal size.  The `units_per_EM` field of @FT_FaceRec is used
 *     to determine both scaling values.
 *
 *     This is the standard scaling found in most applications.  In
 *     particular, use this size request type for TrueType fonts if they
 *     provide optical scaling or something similar.  Note, however, that
 *     `units_per_EM` is a rather abstract value which bears no relation to
 *     the actual size of the glyphs in a font.
 *
 *   FT_SIZE_REQUEST_TYPE_REAL_DIM ::
 *     The real dimension.  The sum of the `ascender` and (minus of) the
 *     `descender` fields of @FT_FaceRec is used to determine both scaling
 *     values.
 *
 *   FT_SIZE_REQUEST_TYPE_BBOX ::
 *     The font bounding box.  The width and height of the `bbox` field of
 *     @FT_FaceRec are used to determine the horizontal and vertical
 *     scaling value, respectively.
 *
 *   FT_SIZE_REQUEST_TYPE_CELL ::
 *     The `max_advance_width` field of @FT_FaceRec is used to determine
 *     the horizontal scaling value; the vertical scaling value is
 *     determined the same way as @FT_SIZE_REQUEST_TYPE_REAL_DIM does.
 *     Finally, both scaling values are set to the smaller one.  This type
 *     is useful if you want to specify the font size for, say, a window of
 *     a given dimension and 80x24 cells.
 *
 *   FT_SIZE_REQUEST_TYPE_SCALES ::
 *     Specify the scaling values directly.
 *
 * @note:
 *   The above descriptions only apply to scalable formats.  For bitmap
 *   formats, the behaviour is up to the driver.
 *
 *   See the note section of @FT_Size_Metrics if you wonder how size
 *   requesting relates to scaling values.
 */
typedef enum FT_Size_Request_Type_ {
	FT_SIZE_REQUEST_TYPE_NOMINAL,
	FT_SIZE_REQUEST_TYPE_REAL_DIM,
	FT_SIZE_REQUEST_TYPE_BBOX,
	FT_SIZE_REQUEST_TYPE_CELL,
	FT_SIZE_REQUEST_TYPE_SCALES,

	FT_SIZE_REQUEST_TYPE_MAX

} FT_Size_Request_Type;

/**************************************************************************
 *
 * @struct:
 *   FT_Size_RequestRec
 *
 * @description:
 *   A structure to model a size request.
 *
 * @fields:
 *   type ::
 *     See @FT_Size_Request_Type.
 *
 *   width ::
 *     The desired width, given as a 26.6 fractional point value (with 72pt
 *     = 1in).
 *
 *   height ::
 *     The desired height, given as a 26.6 fractional point value (with
 *     72pt = 1in).
 *
 *   horiResolution ::
 *     The horizontal resolution (dpi, i.e., pixels per inch).  If set to
 *     zero, `width` is treated as a 26.6 fractional **pixel** value, which
 *     gets internally rounded to an integer.
 *
 *   vertResolution ::
 *     The vertical resolution (dpi, i.e., pixels per inch).  If set to
 *     zero, `height` is treated as a 26.6 fractional **pixel** value,
 *     which gets internally rounded to an integer.
 *
 * @note:
 *   If `width` is zero, the horizontal scaling value is set equal to the
 *   vertical scaling value, and vice versa.
 *
 *   If `type` is `FT_SIZE_REQUEST_TYPE_SCALES`, `width` and `height` are
 *   interpreted directly as 16.16 fractional scaling values, without any
 *   further modification, and both `horiResolution` and `vertResolution`
 *   are ignored.
 */
typedef struct FT_Size_RequestRec_ {
	FT_Size_Request_Type type;
	FT_Long width;
	FT_Long height;
	FT_UInt horiResolution;
	FT_UInt vertResolution;

} FT_Size_RequestRec;

/**************************************************************************
 *
 * @struct:
 *   FT_Size_Request
 *
 * @description:
 *   A handle to a size request structure.
 */
typedef struct FT_Size_RequestRec_ *FT_Size_Request;

/**************************************************************************
 *
 * @function:
 *   FT_Request_Size
 *
 * @description:
 *   Resize the scale of the active @FT_Size object in a face.
 *
 * @inout:
 *   face ::
 *     A handle to a target face object.
 *
 * @input:
 *   req ::
 *     A pointer to a @FT_Size_RequestRec.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   Although drivers may select the bitmap strike matching the request,
 *   you should not rely on this if you intend to select a particular
 *   bitmap strike.  Use @FT_Select_Size instead in that case.
 *
 *   The relation between the requested size and the resulting glyph size
 *   is dependent entirely on how the size is defined in the source face.
 *   The font designer chooses the final size of each glyph relative to
 *   this size.  For more information refer to
 *   'https://www.freetype.org/freetype2/docs/glyphs/glyphs-2.html'.
 *
 *   Contrary to @FT_Set_Char_Size, this function doesn't have special code
 *   to normalize zero-valued widths, heights, or resolutions (which lead
 *   to errors in most cases).
 *
 *   Don't use this function if you are using the FreeType cache API.
 */
FT_EXPORT(FT_Error)
FT_Request_Size(FT_Face face, FT_Size_Request req);

/**************************************************************************
 *
 * @function:
 *   FT_Set_Char_Size
 *
 * @description:
 *   Call @FT_Request_Size to request the nominal size (in points).
 *
 * @inout:
 *   face ::
 *     A handle to a target face object.
 *
 * @input:
 *   char_width ::
 *     The nominal width, in 26.6 fractional points.
 *
 *   char_height ::
 *     The nominal height, in 26.6 fractional points.
 *
 *   horz_resolution ::
 *     The horizontal resolution in dpi.
 *
 *   vert_resolution ::
 *     The vertical resolution in dpi.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   While this function allows fractional points as input values, the
 *   resulting ppem value for the given resolution is always rounded to the
 *   nearest integer.
 *
 *   If either the character width or height is zero, it is set equal to
 *   the other value.
 *
 *   If either the horizontal or vertical resolution is zero, it is set
 *   equal to the other value.
 *
 *   A character width or height smaller than 1pt is set to 1pt; if both
 *   resolution values are zero, they are set to 72dpi.
 *
 *   Don't use this function if you are using the FreeType cache API.
 */
FT_EXPORT(FT_Error)
FT_Set_Char_Size(FT_Face face, FT_F26Dot6 char_width, FT_F26Dot6 char_height,
                 FT_UInt horz_resolution, FT_UInt vert_resolution);

/**************************************************************************
 *
 * @function:
 *   FT_Set_Pixel_Sizes
 *
 * @description:
 *   Call @FT_Request_Size to request the nominal size (in pixels).
 *
 * @inout:
 *   face ::
 *     A handle to the target face object.
 *
 * @input:
 *   pixel_width ::
 *     The nominal width, in pixels.
 *
 *   pixel_height ::
 *     The nominal height, in pixels.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   You should not rely on the resulting glyphs matching or being
 *   constrained to this pixel size.  Refer to @FT_Request_Size to
 *   understand how requested sizes relate to actual sizes.
 *
 *   Don't use this function if you are using the FreeType cache API.
 */
FT_EXPORT(FT_Error)
FT_Set_Pixel_Sizes(FT_Face face, FT_UInt pixel_width, FT_UInt pixel_height);

/**************************************************************************
 *
 * @function:
 *   FT_Load_Glyph
 *
 * @description:
 *   Load a glyph into the glyph slot of a face object.
 *
 * @inout:
 *   face ::
 *     A handle to the target face object where the glyph is loaded.
 *
 * @input:
 *   glyph_index ::
 *     The index of the glyph in the font file.  For CID-keyed fonts
 *     (either in PS or in CFF format) this argument specifies the CID
 *     value.
 *
 *   load_flags ::
 *     A flag indicating what to load for this glyph.  The @FT_LOAD_XXX
 *     constants can be used to control the glyph loading process (e.g.,
 *     whether the outline should be scaled, whether to load bitmaps or
 *     not, whether to hint the outline, etc).
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   The loaded glyph may be transformed.  See @FT_Set_Transform for the
 *   details.
 *
 *   For subsetted CID-keyed fonts, `FT_Err_Invalid_Argument` is returned
 *   for invalid CID values (this is, for CID values that don't have a
 *   corresponding glyph in the font).  See the discussion of the
 *   @FT_FACE_FLAG_CID_KEYED flag for more details.
 *
 *   If you receive `FT_Err_Glyph_Too_Big`, try getting the glyph outline
 *   at EM size, then scale it manually and fill it as a graphics
 *   operation.
 */
FT_EXPORT(FT_Error)
FT_Load_Glyph(FT_Face face, FT_UInt glyph_index, FT_Int32 load_flags);

/**************************************************************************
 *
 * @function:
 *   FT_Load_Char
 *
 * @description:
 *   Load a glyph into the glyph slot of a face object, accessed by its
 *   character code.
 *
 * @inout:
 *   face ::
 *     A handle to a target face object where the glyph is loaded.
 *
 * @input:
 *   char_code ::
 *     The glyph's character code, according to the current charmap used in
 *     the face.
 *
 *   load_flags ::
 *     A flag indicating what to load for this glyph.  The @FT_LOAD_XXX
 *     constants can be used to control the glyph loading process (e.g.,
 *     whether the outline should be scaled, whether to load bitmaps or
 *     not, whether to hint the outline, etc).
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   This function simply calls @FT_Get_Char_Index and @FT_Load_Glyph.
 *
 *   Many fonts contain glyphs that can't be loaded by this function since
 *   its glyph indices are not listed in any of the font's charmaps.
 *
 *   If no active cmap is set up (i.e., `face->charmap` is zero), the call
 *   to @FT_Get_Char_Index is omitted, and the function behaves identically
 *   to @FT_Load_Glyph.
 */
FT_EXPORT(FT_Error)
FT_Load_Char(FT_Face face, FT_ULong char_code, FT_Int32 load_flags);

/**************************************************************************
 *
 * @enum:
 *   FT_LOAD_XXX
 *
 * @description:
 *   A list of bit field constants for @FT_Load_Glyph to indicate what kind
 *   of operations to perform during glyph loading.
 *
 * @values:
 *   FT_LOAD_DEFAULT ::
 *     Corresponding to~0, this value is used as the default glyph load
 *     operation.  In this case, the following happens:
 *
 *     1. FreeType looks for a bitmap for the glyph corresponding to the
 *     face's current size.  If one is found, the function returns.  The
 *     bitmap data can be accessed from the glyph slot (see note below).
 *
 *     2. If no embedded bitmap is searched for or found, FreeType looks
 *     for a scalable outline.  If one is found, it is loaded from the font
 *     file, scaled to device pixels, then 'hinted' to the pixel grid in
 *     order to optimize it.  The outline data can be accessed from the
 *     glyph slot (see note below).
 *
 *     Note that by default the glyph loader doesn't render outlines into
 *     bitmaps.  The following flags are used to modify this default
 *     behaviour to more specific and useful cases.
 *
 *   FT_LOAD_NO_SCALE ::
 *     Don't scale the loaded outline glyph but keep it in font units.
 *
 *     This flag implies @FT_LOAD_NO_HINTING and @FT_LOAD_NO_BITMAP, and
 *     unsets @FT_LOAD_RENDER.
 *
 *     If the font is 'tricky' (see @FT_FACE_FLAG_TRICKY for more), using
 *     `FT_LOAD_NO_SCALE` usually yields meaningless outlines because the
 *     subglyphs must be scaled and positioned with hinting instructions.
 *     This can be solved by loading the font without `FT_LOAD_NO_SCALE`
 *     and setting the character size to `font->units_per_EM`.
 *
 *   FT_LOAD_NO_HINTING ::
 *     Disable hinting.  This generally generates 'blurrier' bitmap glyphs
 *     when the glyph are rendered in any of the anti-aliased modes.  See
 *     also the note below.
 *
 *     This flag is implied by @FT_LOAD_NO_SCALE.
 *
 *   FT_LOAD_RENDER ::
 *     Call @FT_Render_Glyph after the glyph is loaded.  By default, the
 *     glyph is rendered in @FT_RENDER_MODE_NORMAL mode.  This can be
 *     overridden by @FT_LOAD_TARGET_XXX or @FT_LOAD_MONOCHROME.
 *
 *     This flag is unset by @FT_LOAD_NO_SCALE.
 *
 *   FT_LOAD_NO_BITMAP ::
 *     Ignore bitmap strikes when loading.  Bitmap-only fonts ignore this
 *     flag.
 *
 *     @FT_LOAD_NO_SCALE always sets this flag.
 *
 *   FT_LOAD_VERTICAL_LAYOUT ::
 *     Load the glyph for vertical text layout.  In particular, the
 *     `advance` value in the @FT_GlyphSlotRec structure is set to the
 *     `vertAdvance` value of the `metrics` field.
 *
 *     In case @FT_HAS_VERTICAL doesn't return true, you shouldn't use this
 *     flag currently.  Reason is that in this case vertical metrics get
 *     synthesized, and those values are not always consistent across
 *     various font formats.
 *
 *   FT_LOAD_FORCE_AUTOHINT ::
 *     Prefer the auto-hinter over the font's native hinter.  See also the
 *     note below.
 *
 *   FT_LOAD_PEDANTIC ::
 *     Make the font driver perform pedantic verifications during glyph
 *     loading and hinting.  This is mostly used to detect broken glyphs in
 *     fonts.  By default, FreeType tries to handle broken fonts also.
 *
 *     In particular, errors from the TrueType bytecode engine are not
 *     passed to the application if this flag is not set; this might result
 *     in partially hinted or distorted glyphs in case a glyph's bytecode
 *     is buggy.
 *
 *   FT_LOAD_NO_RECURSE ::
 *     Don't load composite glyphs recursively.  Instead, the font driver
 *     fills the `num_subglyph` and `subglyphs` values of the glyph slot;
 *     it also sets `glyph->format` to @FT_GLYPH_FORMAT_COMPOSITE.  The
 *     description of subglyphs can then be accessed with
 *     @FT_Get_SubGlyph_Info.
 *
 *     Don't use this flag for retrieving metrics information since some
 *     font drivers only return rudimentary data.
 *
 *     This flag implies @FT_LOAD_NO_SCALE and @FT_LOAD_IGNORE_TRANSFORM.
 *
 *   FT_LOAD_IGNORE_TRANSFORM ::
 *     Ignore the transform matrix set by @FT_Set_Transform.
 *
 *   FT_LOAD_MONOCHROME ::
 *     This flag is used with @FT_LOAD_RENDER to indicate that you want to
 *     render an outline glyph to a 1-bit monochrome bitmap glyph, with
 *     8~pixels packed into each byte of the bitmap data.
 *
 *     Note that this has no effect on the hinting algorithm used.  You
 *     should rather use @FT_LOAD_TARGET_MONO so that the
 *     monochrome-optimized hinting algorithm is used.
 *
 *   FT_LOAD_LINEAR_DESIGN ::
 *     Keep `linearHoriAdvance` and `linearVertAdvance` fields of
 *     @FT_GlyphSlotRec in font units.  See @FT_GlyphSlotRec for details.
 *
 *   FT_LOAD_NO_AUTOHINT ::
 *     Disable the auto-hinter.  See also the note below.
 *
 *   FT_LOAD_COLOR ::
 *     Load colored glyphs.  There are slight differences depending on the
 *     font format.
 *
 *     [Since 2.5] Load embedded color bitmap images.  The resulting color
 *     bitmaps, if available, will have the @FT_PIXEL_MODE_BGRA format,
 *     with pre-multiplied color channels.  If the flag is not set and
 *     color bitmaps are found, they are converted to 256-level gray
 *     bitmaps, using the @FT_PIXEL_MODE_GRAY format.
 *
 *     [Since 2.10, experimental] If the glyph index contains an entry in
 *     the face's 'COLR' table with a 'CPAL' palette table (as defined in
 *     the OpenType specification), make @FT_Render_Glyph provide a default
 *     blending of the color glyph layers associated with the glyph index,
 *     using the same bitmap format as embedded color bitmap images.  This
 *     is mainly for convenience; for full control of color layers use
 *     @FT_Get_Color_Glyph_Layer and FreeType's color functions like
 *     @FT_Palette_Select instead of setting @FT_LOAD_COLOR for rendering
 *     so that the client application can handle blending by itself.
 *
 *   FT_LOAD_COMPUTE_METRICS ::
 *     [Since 2.6.1] Compute glyph metrics from the glyph data, without the
 *     use of bundled metrics tables (for example, the 'hdmx' table in
 *     TrueType fonts).  This flag is mainly used by font validating or
 *     font editing applications, which need to ignore, verify, or edit
 *     those tables.
 *
 *     Currently, this flag is only implemented for TrueType fonts.
 *
 *   FT_LOAD_BITMAP_METRICS_ONLY ::
 *     [Since 2.7.1] Request loading of the metrics and bitmap image
 *     information of a (possibly embedded) bitmap glyph without allocating
 *     or copying the bitmap image data itself.  No effect if the target
 *     glyph is not a bitmap image.
 *
 *     This flag unsets @FT_LOAD_RENDER.
 *
 *   FT_LOAD_CROP_BITMAP ::
 *     Ignored.  Deprecated.
 *
 *   FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH ::
 *     Ignored.  Deprecated.
 *
 * @note:
 *   By default, hinting is enabled and the font's native hinter (see
 *   @FT_FACE_FLAG_HINTER) is preferred over the auto-hinter.  You can
 *   disable hinting by setting @FT_LOAD_NO_HINTING or change the
 *   precedence by setting @FT_LOAD_FORCE_AUTOHINT.  You can also set
 *   @FT_LOAD_NO_AUTOHINT in case you don't want the auto-hinter to be used
 *   at all.
 *
 *   See the description of @FT_FACE_FLAG_TRICKY for a special exception
 *   (affecting only a handful of Asian fonts).
 *
 *   Besides deciding which hinter to use, you can also decide which
 *   hinting algorithm to use.  See @FT_LOAD_TARGET_XXX for details.
 *
 *   Note that the auto-hinter needs a valid Unicode cmap (either a native
 *   one or synthesized by FreeType) for producing correct results.  If a
 *   font provides an incorrect mapping (for example, assigning the
 *   character code U+005A, LATIN CAPITAL LETTER~Z, to a glyph depicting a
 *   mathematical integral sign), the auto-hinter might produce useless
 *   results.
 *
 */
#define FT_LOAD_DEFAULT 0x0
#define FT_LOAD_NO_SCALE (1L << 0)
#define FT_LOAD_NO_HINTING (1L << 1)
#define FT_LOAD_RENDER (1L << 2)
#define FT_LOAD_NO_BITMAP (1L << 3)
#define FT_LOAD_VERTICAL_LAYOUT (1L << 4)
#define FT_LOAD_FORCE_AUTOHINT (1L << 5)
#define FT_LOAD_CROP_BITMAP (1L << 6)
#define FT_LOAD_PEDANTIC (1L << 7)
#define FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH (1L << 9)
#define FT_LOAD_NO_RECURSE (1L << 10)
#define FT_LOAD_IGNORE_TRANSFORM (1L << 11)
#define FT_LOAD_MONOCHROME (1L << 12)
#define FT_LOAD_LINEAR_DESIGN (1L << 13)
#define FT_LOAD_NO_AUTOHINT (1L << 15)
/* Bits 16-19 are used by `FT_LOAD_TARGET_` */
#define FT_LOAD_COLOR (1L << 20)
#define FT_LOAD_COMPUTE_METRICS (1L << 21)
#define FT_LOAD_BITMAP_METRICS_ONLY (1L << 22)

/* */

/* used internally only by certain font drivers */
#define FT_LOAD_ADVANCE_ONLY (1L << 8)
#define FT_LOAD_SBITS_ONLY (1L << 14)

/**************************************************************************
 *
 * @enum:
 *   FT_LOAD_TARGET_XXX
 *
 * @description:
 *   A list of values to select a specific hinting algorithm for the
 *   hinter.  You should OR one of these values to your `load_flags` when
 *   calling @FT_Load_Glyph.
 *
 *   Note that a font's native hinters may ignore the hinting algorithm you
 *   have specified (e.g., the TrueType bytecode interpreter).  You can set
 *   @FT_LOAD_FORCE_AUTOHINT to ensure that the auto-hinter is used.
 *
 * @values:
 *   FT_LOAD_TARGET_NORMAL ::
 *     The default hinting algorithm, optimized for standard gray-level
 *     rendering.  For monochrome output, use @FT_LOAD_TARGET_MONO instead.
 *
 *   FT_LOAD_TARGET_LIGHT ::
 *     A lighter hinting algorithm for gray-level modes.  Many generated
 *     glyphs are fuzzier but better resemble their original shape.  This
 *     is achieved by snapping glyphs to the pixel grid only vertically
 *     (Y-axis), as is done by FreeType's new CFF engine or Microsoft's
 *     ClearType font renderer.  This preserves inter-glyph spacing in
 *     horizontal text.  The snapping is done either by the native font
 *     driver, if the driver itself and the font support it, or by the
 *     auto-hinter.
 *
 *     Advance widths are rounded to integer values; however, using the
 *     `lsb_delta` and `rsb_delta` fields of @FT_GlyphSlotRec, it is
 *     possible to get fractional advance widths for subpixel positioning
 *     (which is recommended to use).
 *
 *     If configuration option `AF_CONFIG_OPTION_TT_SIZE_METRICS` is
 *     active, TrueType-like metrics are used to make this mode behave
 *     similarly as in unpatched FreeType versions between 2.4.6 and 2.7.1
 *     (inclusive).
 *
 *   FT_LOAD_TARGET_MONO ::
 *     Strong hinting algorithm that should only be used for monochrome
 *     output.  The result is probably unpleasant if the glyph is rendered
 *     in non-monochrome modes.
 *
 *     Note that for outline fonts only the TrueType font driver has proper
 *     monochrome hinting support, provided the TTFs contain hints for B/W
 *     rendering (which most fonts no longer provide).  If these conditions
 *     are not met it is very likely that you get ugly results at smaller
 *     sizes.
 *
 *   FT_LOAD_TARGET_LCD ::
 *     A variant of @FT_LOAD_TARGET_LIGHT optimized for horizontally
 *     decimated LCD displays.
 *
 *   FT_LOAD_TARGET_LCD_V ::
 *     A variant of @FT_LOAD_TARGET_NORMAL optimized for vertically
 *     decimated LCD displays.
 *
 * @note:
 *   You should use only _one_ of the `FT_LOAD_TARGET_XXX` values in your
 *   `load_flags`.  They can't be ORed.
 *
 *   If @FT_LOAD_RENDER is also set, the glyph is rendered in the
 *   corresponding mode (i.e., the mode that matches the used algorithm
 *   best).  An exception is `FT_LOAD_TARGET_MONO` since it implies
 *   @FT_LOAD_MONOCHROME.
 *
 *   You can use a hinting algorithm that doesn't correspond to the same
 *   rendering mode.  As an example, it is possible to use the 'light'
 *   hinting algorithm and have the results rendered in horizontal LCD
 *   pixel mode, with code like
 *
 *   ```
 *     FT_Load_Glyph( face, glyph_index,
 *                    load_flags | FT_LOAD_TARGET_LIGHT );
 *
 *     FT_Render_Glyph( face->glyph, FT_RENDER_MODE_LCD );
 *   ```
 *
 *   In general, you should stick with one rendering mode.  For example,
 *   switching between @FT_LOAD_TARGET_NORMAL and @FT_LOAD_TARGET_MONO
 *   enforces a lot of recomputation for TrueType fonts, which is slow.
 *   Another reason is caching: Selecting a different mode usually causes
 *   changes in both the outlines and the rasterized bitmaps; it is thus
 *   necessary to empty the cache after a mode switch to avoid false hits.
 *
 */
#define FT_LOAD_TARGET_(x) ((FT_Int32)((x)&15) << 16)

#define FT_LOAD_TARGET_NORMAL FT_LOAD_TARGET_(FT_RENDER_MODE_NORMAL)
#define FT_LOAD_TARGET_LIGHT FT_LOAD_TARGET_(FT_RENDER_MODE_LIGHT)
#define FT_LOAD_TARGET_MONO FT_LOAD_TARGET_(FT_RENDER_MODE_MONO)
#define FT_LOAD_TARGET_LCD FT_LOAD_TARGET_(FT_RENDER_MODE_LCD)
#define FT_LOAD_TARGET_LCD_V FT_LOAD_TARGET_(FT_RENDER_MODE_LCD_V)

/**************************************************************************
 *
 * @macro:
 *   FT_LOAD_TARGET_MODE
 *
 * @description:
 *   Return the @FT_Render_Mode corresponding to a given
 *   @FT_LOAD_TARGET_XXX value.
 *
 */
#define FT_LOAD_TARGET_MODE(x) ((FT_Render_Mode)(((x) >> 16) & 15))

/**************************************************************************
 *
 * @function:
 *   FT_Set_Transform
 *
 * @description:
 *   Set the transformation that is applied to glyph images when they are
 *   loaded into a glyph slot through @FT_Load_Glyph.
 *
 * @inout:
 *   face ::
 *     A handle to the source face object.
 *
 * @input:
 *   matrix ::
 *     A pointer to the transformation's 2x2 matrix.  Use `NULL` for the
 *     identity matrix.
 *   delta ::
 *     A pointer to the translation vector.  Use `NULL` for the null vector.
 *
 * @note:
 *   The transformation is only applied to scalable image formats after the
 *   glyph has been loaded.  It means that hinting is unaltered by the
 *   transformation and is performed on the character size given in the
 *   last call to @FT_Set_Char_Size or @FT_Set_Pixel_Sizes.
 *
 *   Note that this also transforms the `face.glyph.advance` field, but
 *   **not** the values in `face.glyph.metrics`.
 */
FT_EXPORT(void)
FT_Set_Transform(FT_Face face, FT_Matrix *matrix, FT_Vector *delta);

/**************************************************************************
 *
 * @enum:
 *   FT_Render_Mode
 *
 * @description:
 *   Render modes supported by FreeType~2.  Each mode corresponds to a
 *   specific type of scanline conversion performed on the outline.
 *
 *   For bitmap fonts and embedded bitmaps the `bitmap->pixel_mode` field
 *   in the @FT_GlyphSlotRec structure gives the format of the returned
 *   bitmap.
 *
 *   All modes except @FT_RENDER_MODE_MONO use 256 levels of opacity,
 *   indicating pixel coverage.  Use linear alpha blending and gamma
 *   correction to correctly render non-monochrome glyph bitmaps onto a
 *   surface; see @FT_Render_Glyph.
 *
 * @values:
 *   FT_RENDER_MODE_NORMAL ::
 *     Default render mode; it corresponds to 8-bit anti-aliased bitmaps.
 *
 *   FT_RENDER_MODE_LIGHT ::
 *     This is equivalent to @FT_RENDER_MODE_NORMAL.  It is only defined as
 *     a separate value because render modes are also used indirectly to
 *     define hinting algorithm selectors.  See @FT_LOAD_TARGET_XXX for
 *     details.
 *
 *   FT_RENDER_MODE_MONO ::
 *     This mode corresponds to 1-bit bitmaps (with 2~levels of opacity).
 *
 *   FT_RENDER_MODE_LCD ::
 *     This mode corresponds to horizontal RGB and BGR subpixel displays
 *     like LCD screens.  It produces 8-bit bitmaps that are 3~times the
 *     width of the original glyph outline in pixels, and which use the
 *     @FT_PIXEL_MODE_LCD mode.
 *
 *   FT_RENDER_MODE_LCD_V ::
 *     This mode corresponds to vertical RGB and BGR subpixel displays
 *     (like PDA screens, rotated LCD displays, etc.).  It produces 8-bit
 *     bitmaps that are 3~times the height of the original glyph outline in
 *     pixels and use the @FT_PIXEL_MODE_LCD_V mode.
 *
 * @note:
 *   Should you define `FT_CONFIG_OPTION_SUBPIXEL_RENDERING` in your
 *   `ftoption.h`, which enables patented ClearType-style rendering, the
 *   LCD-optimized glyph bitmaps should be filtered to reduce color fringes
 *   inherent to this technology.  You can either set up LCD filtering with
 *   @FT_Library_SetLcdFilter or @FT_Face_Properties, or do the filtering
 *   yourself.  The default FreeType LCD rendering technology does not
 *   require filtering.
 *
 *   The selected render mode only affects vector glyphs of a font.
 *   Embedded bitmaps often have a different pixel mode like
 *   @FT_PIXEL_MODE_MONO.  You can use @FT_Bitmap_Convert to transform them
 *   into 8-bit pixmaps.
 */
typedef enum FT_Render_Mode_ {
	FT_RENDER_MODE_NORMAL = 0,
	FT_RENDER_MODE_LIGHT,
	FT_RENDER_MODE_MONO,
	FT_RENDER_MODE_LCD,
	FT_RENDER_MODE_LCD_V,

	FT_RENDER_MODE_MAX

} FT_Render_Mode;

/* these constants are deprecated; use the corresponding */
/* `FT_Render_Mode` values instead                       */
#define ft_render_mode_normal FT_RENDER_MODE_NORMAL
#define ft_render_mode_mono FT_RENDER_MODE_MONO

/**************************************************************************
 *
 * @function:
 *   FT_Render_Glyph
 *
 * @description:
 *   Convert a given glyph image to a bitmap.  It does so by inspecting the
 *   glyph image format, finding the relevant renderer, and invoking it.
 *
 * @inout:
 *   slot ::
 *     A handle to the glyph slot containing the image to convert.
 *
 * @input:
 *   render_mode ::
 *     The render mode used to render the glyph image into a bitmap.  See
 *     @FT_Render_Mode for a list of possible values.
 *
 *     If @FT_RENDER_MODE_NORMAL is used, a previous call of @FT_Load_Glyph
 *     with flag @FT_LOAD_COLOR makes FT_Render_Glyph provide a default
 *     blending of colored glyph layers associated with the current glyph
 *     slot (provided the font contains such layers) instead of rendering
 *     the glyph slot's outline.  This is an experimental feature; see
 *     @FT_LOAD_COLOR for more information.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   To get meaningful results, font scaling values must be set with
 *   functions like @FT_Set_Char_Size before calling `FT_Render_Glyph`.
 *
 *   When FreeType outputs a bitmap of a glyph, it really outputs an alpha
 *   coverage map.  If a pixel is completely covered by a filled-in
 *   outline, the bitmap contains 0xFF at that pixel, meaning that
 *   0xFF/0xFF fraction of that pixel is covered, meaning the pixel is 100%
 *   black (or 0% bright).  If a pixel is only 50% covered (value 0x80),
 *   the pixel is made 50% black (50% bright or a middle shade of grey).
 *   0% covered means 0% black (100% bright or white).
 *
 *   On high-DPI screens like on smartphones and tablets, the pixels are so
 *   small that their chance of being completely covered and therefore
 *   completely black are fairly good.  On the low-DPI screens, however,
 *   the situation is different.  The pixels are too large for most of the
 *   details of a glyph and shades of gray are the norm rather than the
 *   exception.
 *
 *   This is relevant because all our screens have a second problem: they
 *   are not linear.  1~+~1 is not~2.  Twice the value does not result in
 *   twice the brightness.  When a pixel is only 50% covered, the coverage
 *   map says 50% black, and this translates to a pixel value of 128 when
 *   you use 8~bits per channel (0-255).  However, this does not translate
 *   to 50% brightness for that pixel on our sRGB and gamma~2.2 screens.
 *   Due to their non-linearity, they dwell longer in the darks and only a
 *   pixel value of about 186 results in 50% brightness -- 128 ends up too
 *   dark on both bright and dark backgrounds.  The net result is that dark
 *   text looks burnt-out, pixely and blotchy on bright background, bright
 *   text too frail on dark backgrounds, and colored text on colored
 *   background (for example, red on green) seems to have dark halos or
 *   'dirt' around it.  The situation is especially ugly for diagonal stems
 *   like in 'w' glyph shapes where the quality of FreeType's anti-aliasing
 *   depends on the correct display of grays.  On high-DPI screens where
 *   smaller, fully black pixels reign supreme, this doesn't matter, but on
 *   our low-DPI screens with all the gray shades, it does.  0% and 100%
 *   brightness are the same things in linear and non-linear space, just
 *   all the shades in-between aren't.
 *
 *   The blending function for placing text over a background is
 *
 *   ```
 *     dst = alpha * src + (1 - alpha) * dst    ,
 *   ```
 *
 *   which is known as the OVER operator.
 *
 *   To correctly composite an antialiased pixel of a glyph onto a surface,
 *
 *   1. take the foreground and background colors (e.g., in sRGB space)
 *      and apply gamma to get them in a linear space,
 *
 *   2. use OVER to blend the two linear colors using the glyph pixel
 *      as the alpha value (remember, the glyph bitmap is an alpha coverage
 *      bitmap), and
 *
 *   3. apply inverse gamma to the blended pixel and write it back to
 *      the image.
 *
 *   Internal testing at Adobe found that a target inverse gamma of~1.8 for
 *   step~3 gives good results across a wide range of displays with an sRGB
 *   gamma curve or a similar one.
 *
 *   This process can cost performance.  There is an approximation that
 *   does not need to know about the background color; see
 *   https://bel.fi/alankila/lcd/ and
 *   https://bel.fi/alankila/lcd/alpcor.html for details.
 *
 *   **ATTENTION**: Linear blending is even more important when dealing
 *   with subpixel-rendered glyphs to prevent color-fringing!  A
 *   subpixel-rendered glyph must first be filtered with a filter that
 *   gives equal weight to the three color primaries and does not exceed a
 *   sum of 0x100, see section @lcd_rendering.  Then the only difference to
 *   gray linear blending is that subpixel-rendered linear blending is done
 *   3~times per pixel: red foreground subpixel to red background subpixel
 *   and so on for green and blue.
 */
FT_EXPORT(FT_Error)
FT_Render_Glyph(FT_GlyphSlot slot, FT_Render_Mode render_mode);

/**************************************************************************
 *
 * @enum:
 *   FT_Kerning_Mode
 *
 * @description:
 *   An enumeration to specify the format of kerning values returned by
 *   @FT_Get_Kerning.
 *
 * @values:
 *   FT_KERNING_DEFAULT ::
 *     Return grid-fitted kerning distances in 26.6 fractional pixels.
 *
 *   FT_KERNING_UNFITTED ::
 *     Return un-grid-fitted kerning distances in 26.6 fractional pixels.
 *
 *   FT_KERNING_UNSCALED ::
 *     Return the kerning vector in original font units.
 *
 * @note:
 *   `FT_KERNING_DEFAULT` returns full pixel values; it also makes FreeType
 *   heuristically scale down kerning distances at small ppem values so
 *   that they don't become too big.
 *
 *   Both `FT_KERNING_DEFAULT` and `FT_KERNING_UNFITTED` use the current
 *   horizontal scaling factor (as set e.g. with @FT_Set_Char_Size) to
 *   convert font units to pixels.
 */
typedef enum FT_Kerning_Mode_ {
	FT_KERNING_DEFAULT = 0,
	FT_KERNING_UNFITTED,
	FT_KERNING_UNSCALED

} FT_Kerning_Mode;

/* these constants are deprecated; use the corresponding */
/* `FT_Kerning_Mode` values instead                      */
#define ft_kerning_default FT_KERNING_DEFAULT
#define ft_kerning_unfitted FT_KERNING_UNFITTED
#define ft_kerning_unscaled FT_KERNING_UNSCALED

/**************************************************************************
 *
 * @function:
 *   FT_Get_Kerning
 *
 * @description:
 *   Return the kerning vector between two glyphs of the same face.
 *
 * @input:
 *   face ::
 *     A handle to a source face object.
 *
 *   left_glyph ::
 *     The index of the left glyph in the kern pair.
 *
 *   right_glyph ::
 *     The index of the right glyph in the kern pair.
 *
 *   kern_mode ::
 *     See @FT_Kerning_Mode for more information.  Determines the scale and
 *     dimension of the returned kerning vector.
 *
 * @output:
 *   akerning ::
 *     The kerning vector.  This is either in font units, fractional pixels
 *     (26.6 format), or pixels for scalable formats, and in pixels for
 *     fixed-sizes formats.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   Only horizontal layouts (left-to-right & right-to-left) are supported
 *   by this method.  Other layouts, or more sophisticated kernings, are
 *   out of the scope of this API function -- they can be implemented
 *   through format-specific interfaces.
 *
 *   Kerning for OpenType fonts implemented in a 'GPOS' table is not
 *   supported; use @FT_HAS_KERNING to find out whether a font has data
 *   that can be extracted with `FT_Get_Kerning`.
 */
FT_EXPORT(FT_Error)
FT_Get_Kerning(FT_Face face, FT_UInt left_glyph, FT_UInt right_glyph, FT_UInt kern_mode,
               FT_Vector *akerning);

/**************************************************************************
 *
 * @function:
 *   FT_Get_Track_Kerning
 *
 * @description:
 *   Return the track kerning for a given face object at a given size.
 *
 * @input:
 *   face ::
 *     A handle to a source face object.
 *
 *   point_size ::
 *     The point size in 16.16 fractional points.
 *
 *   degree ::
 *     The degree of tightness.  Increasingly negative values represent
 *     tighter track kerning, while increasingly positive values represent
 *     looser track kerning.  Value zero means no track kerning.
 *
 * @output:
 *   akerning ::
 *     The kerning in 16.16 fractional points, to be uniformly applied
 *     between all glyphs.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   Currently, only the Type~1 font driver supports track kerning, using
 *   data from AFM files (if attached with @FT_Attach_File or
 *   @FT_Attach_Stream).
 *
 *   Only very few AFM files come with track kerning data; please refer to
 *   Adobe's AFM specification for more details.
 */
FT_EXPORT(FT_Error)
FT_Get_Track_Kerning(FT_Face face, FT_Fixed point_size, FT_Int degree, FT_Fixed *akerning);

/**************************************************************************
 *
 * @function:
 *   FT_Get_Glyph_Name
 *
 * @description:
 *   Retrieve the ASCII name of a given glyph in a face.  This only works
 *   for those faces where @FT_HAS_GLYPH_NAMES(face) returns~1.
 *
 * @input:
 *   face ::
 *     A handle to a source face object.
 *
 *   glyph_index ::
 *     The glyph index.
 *
 *   buffer_max ::
 *     The maximum number of bytes available in the buffer.
 *
 * @output:
 *   buffer ::
 *     A pointer to a target buffer where the name is copied to.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   An error is returned if the face doesn't provide glyph names or if the
 *   glyph index is invalid.  In all cases of failure, the first byte of
 *   `buffer` is set to~0 to indicate an empty name.
 *
 *   The glyph name is truncated to fit within the buffer if it is too
 *   long.  The returned string is always zero-terminated.
 *
 *   Be aware that FreeType reorders glyph indices internally so that glyph
 *   index~0 always corresponds to the 'missing glyph' (called '.notdef').
 *
 *   This function always returns an error if the config macro
 *   `FT_CONFIG_OPTION_NO_GLYPH_NAMES` is not defined in `ftoption.h`.
 */
FT_EXPORT(FT_Error)
FT_Get_Glyph_Name(FT_Face face, FT_UInt glyph_index, FT_Pointer buffer, FT_UInt buffer_max);

/**************************************************************************
 *
 * @function:
 *   FT_Get_Postscript_Name
 *
 * @description:
 *   Retrieve the ASCII PostScript name of a given face, if available.
 *   This only works with PostScript, TrueType, and OpenType fonts.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 * @return:
 *   A pointer to the face's PostScript name.  `NULL` if unavailable.
 *
 * @note:
 *   The returned pointer is owned by the face and is destroyed with it.
 *
 *   For variation fonts, this string changes if you select a different
 *   instance, and you have to call `FT_Get_PostScript_Name` again to
 *   retrieve it.  FreeType follows Adobe TechNote #5902, 'Generating
 *   PostScript Names for Fonts Using OpenType Font Variations'.
 *
 *     https://download.macromedia.com/pub/developer/opentype/tech-notes/5902.AdobePSNameGeneration.html
 *
 *   [Since 2.9] Special PostScript names for named instances are only
 *   returned if the named instance is set with @FT_Set_Named_Instance (and
 *   the font has corresponding entries in its 'fvar' table).  If
 *   @FT_IS_VARIATION returns true, the algorithmically derived PostScript
 *   name is provided, not looking up special entries for named instances.
 */
FT_EXPORT(const char *)
FT_Get_Postscript_Name(FT_Face face);

/**************************************************************************
 *
 * @function:
 *   FT_Select_Charmap
 *
 * @description:
 *   Select a given charmap by its encoding tag (as listed in
 *   `freetype.h`).
 *
 * @inout:
 *   face ::
 *     A handle to the source face object.
 *
 * @input:
 *   encoding ::
 *     A handle to the selected encoding.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   This function returns an error if no charmap in the face corresponds
 *   to the encoding queried here.
 *
 *   Because many fonts contain more than a single cmap for Unicode
 *   encoding, this function has some special code to select the one that
 *   covers Unicode best ('best' in the sense that a UCS-4 cmap is
 *   preferred to a UCS-2 cmap).  It is thus preferable to @FT_Set_Charmap
 *   in this case.
 */
FT_EXPORT(FT_Error)
FT_Select_Charmap(FT_Face face, FT_Encoding encoding);

/**************************************************************************
 *
 * @function:
 *   FT_Set_Charmap
 *
 * @description:
 *   Select a given charmap for character code to glyph index mapping.
 *
 * @inout:
 *   face ::
 *     A handle to the source face object.
 *
 * @input:
 *   charmap ::
 *     A handle to the selected charmap.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   This function returns an error if the charmap is not part of the face
 *   (i.e., if it is not listed in the `face->charmaps` table).
 *
 *   It also fails if an OpenType type~14 charmap is selected (which
 *   doesn't map character codes to glyph indices at all).
 */
FT_EXPORT(FT_Error)
FT_Set_Charmap(FT_Face face, FT_CharMap charmap);

/**************************************************************************
 *
 * @function:
 *   FT_Get_Charmap_Index
 *
 * @description:
 *   Retrieve index of a given charmap.
 *
 * @input:
 *   charmap ::
 *     A handle to a charmap.
 *
 * @return:
 *   The index into the array of character maps within the face to which
 *   `charmap` belongs.  If an error occurs, -1 is returned.
 *
 */
FT_EXPORT(FT_Int)
FT_Get_Charmap_Index(FT_CharMap charmap);

/**************************************************************************
 *
 * @function:
 *   FT_Get_Char_Index
 *
 * @description:
 *   Return the glyph index of a given character code.  This function uses
 *   the currently selected charmap to do the mapping.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 *   charcode ::
 *     The character code.
 *
 * @return:
 *   The glyph index.  0~means 'undefined character code'.
 *
 * @note:
 *   If you use FreeType to manipulate the contents of font files directly,
 *   be aware that the glyph index returned by this function doesn't always
 *   correspond to the internal indices used within the file.  This is done
 *   to ensure that value~0 always corresponds to the 'missing glyph'.  If
 *   the first glyph is not named '.notdef', then for Type~1 and Type~42
 *   fonts, '.notdef' will be moved into the glyph ID~0 position, and
 *   whatever was there will be moved to the position '.notdef' had.  For
 *   Type~1 fonts, if there is no '.notdef' glyph at all, then one will be
 *   created at index~0 and whatever was there will be moved to the last
 *   index -- Type~42 fonts are considered invalid under this condition.
 */
FT_EXPORT(FT_UInt)
FT_Get_Char_Index(FT_Face face, FT_ULong charcode);

/**************************************************************************
 *
 * @function:
 *   FT_Get_First_Char
 *
 * @description:
 *   Return the first character code in the current charmap of a given
 *   face, together with its corresponding glyph index.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 * @output:
 *   agindex ::
 *     Glyph index of first character code.  0~if charmap is empty.
 *
 * @return:
 *   The charmap's first character code.
 *
 * @note:
 *   You should use this function together with @FT_Get_Next_Char to parse
 *   all character codes available in a given charmap.  The code should
 *   look like this:
 *
 *   ```
 *     FT_ULong  charcode;
 *     FT_UInt   gindex;
 *
 *
 *     charcode = FT_Get_First_Char( face, &gindex );
 *     while ( gindex != 0 )
 *     {
 *       ... do something with (charcode,gindex) pair ...
 *
 *       charcode = FT_Get_Next_Char( face, charcode, &gindex );
 *     }
 *   ```
 *
 *   Be aware that character codes can have values up to 0xFFFFFFFF; this
 *   might happen for non-Unicode or malformed cmaps.  However, even with
 *   regular Unicode encoding, so-called 'last resort fonts' (using SFNT
 *   cmap format 13, see function @FT_Get_CMap_Format) normally have
 *   entries for all Unicode characters up to 0x1FFFFF, which can cause *a
 *   lot* of iterations.
 *
 *   Note that `*agindex` is set to~0 if the charmap is empty.  The result
 *   itself can be~0 in two cases: if the charmap is empty or if the
 *   value~0 is the first valid character code.
 */
FT_EXPORT(FT_ULong)
FT_Get_First_Char(FT_Face face, FT_UInt *agindex);

/**************************************************************************
 *
 * @function:
 *   FT_Get_Next_Char
 *
 * @description:
 *   Return the next character code in the current charmap of a given face
 *   following the value `char_code`, as well as the corresponding glyph
 *   index.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 *   char_code ::
 *     The starting character code.
 *
 * @output:
 *   agindex ::
 *     Glyph index of next character code.  0~if charmap is empty.
 *
 * @return:
 *   The charmap's next character code.
 *
 * @note:
 *   You should use this function with @FT_Get_First_Char to walk over all
 *   character codes available in a given charmap.  See the note for that
 *   function for a simple code example.
 *
 *   Note that `*agindex` is set to~0 when there are no more codes in the
 *   charmap.
 */
FT_EXPORT(FT_ULong)
FT_Get_Next_Char(FT_Face face, FT_ULong char_code, FT_UInt *agindex);

/**************************************************************************
 *
 * @function:
 *   FT_Face_Properties
 *
 * @description:
 *   Set or override certain (library or module-wide) properties on a
 *   face-by-face basis.  Useful for finer-grained control and avoiding
 *   locks on shared structures (threads can modify their own faces as they
 *   see fit).
 *
 *   Contrary to @FT_Property_Set, this function uses @FT_Parameter so that
 *   you can pass multiple properties to the target face in one call.  Note
 *   that only a subset of the available properties can be controlled.
 *
 *   * @FT_PARAM_TAG_STEM_DARKENING (stem darkening, corresponding to the
 *     property `no-stem-darkening` provided by the 'autofit', 'cff',
 *     'type1', and 't1cid' modules; see @no-stem-darkening).
 *
 *   * @FT_PARAM_TAG_LCD_FILTER_WEIGHTS (LCD filter weights, corresponding
 *     to function @FT_Library_SetLcdFilterWeights).
 *
 *   * @FT_PARAM_TAG_RANDOM_SEED (seed value for the CFF, Type~1, and CID
 *     'random' operator, corresponding to the `random-seed` property
 *     provided by the 'cff', 'type1', and 't1cid' modules; see
 *     @random-seed).
 *
 *   Pass `NULL` as `data` in @FT_Parameter for a given tag to reset the
 *   option and use the library or module default again.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 *   num_properties ::
 *     The number of properties that follow.
 *
 *   properties ::
 *     A handle to an @FT_Parameter array with `num_properties` elements.
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @example:
 *   Here is an example that sets three properties.  You must define
 *   `FT_CONFIG_OPTION_SUBPIXEL_RENDERING` to make the LCD filter examples
 *   work.
 *
 *   ```
 *     FT_Parameter         property1;
 *     FT_Bool              darken_stems = 1;
 *
 *     FT_Parameter         property2;
 *     FT_LcdFiveTapFilter  custom_weight =
 *                            { 0x11, 0x44, 0x56, 0x44, 0x11 };
 *
 *     FT_Parameter         property3;
 *     FT_Int32             random_seed = 314159265;
 *
 *     FT_Parameter         properties[3] = { property1,
 *                                            property2,
 *                                            property3 };
 *
 *
 *     property1.tag  = FT_PARAM_TAG_STEM_DARKENING;
 *     property1.data = &darken_stems;
 *
 *     property2.tag  = FT_PARAM_TAG_LCD_FILTER_WEIGHTS;
 *     property2.data = custom_weight;
 *
 *     property3.tag  = FT_PARAM_TAG_RANDOM_SEED;
 *     property3.data = &random_seed;
 *
 *     FT_Face_Properties( face, 3, properties );
 *   ```
 *
 *   The next example resets a single property to its default value.
 *
 *   ```
 *     FT_Parameter  property;
 *
 *
 *     property.tag  = FT_PARAM_TAG_LCD_FILTER_WEIGHTS;
 *     property.data = NULL;
 *
 *     FT_Face_Properties( face, 1, &property );
 *   ```
 *
 * @since:
 *   2.8
 *
 */
FT_EXPORT(FT_Error)
FT_Face_Properties(FT_Face face, FT_UInt num_properties, FT_Parameter *properties);

/**************************************************************************
 *
 * @function:
 *   FT_Get_Name_Index
 *
 * @description:
 *   Return the glyph index of a given glyph name.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 *   glyph_name ::
 *     The glyph name.
 *
 * @return:
 *   The glyph index.  0~means 'undefined character code'.
 */
FT_EXPORT(FT_UInt)
FT_Get_Name_Index(FT_Face face, const FT_String *glyph_name);

/**************************************************************************
 *
 * @enum:
 *   FT_SUBGLYPH_FLAG_XXX
 *
 * @description:
 *   A list of constants describing subglyphs.  Please refer to the 'glyf'
 *   table description in the OpenType specification for the meaning of the
 *   various flags (which get synthesized for non-OpenType subglyphs).
 *
 *     https://docs.microsoft.com/en-us/typography/opentype/spec/glyf#composite-glyph-description
 *
 * @values:
 *   FT_SUBGLYPH_FLAG_ARGS_ARE_WORDS ::
 *   FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES ::
 *   FT_SUBGLYPH_FLAG_ROUND_XY_TO_GRID ::
 *   FT_SUBGLYPH_FLAG_SCALE ::
 *   FT_SUBGLYPH_FLAG_XY_SCALE ::
 *   FT_SUBGLYPH_FLAG_2X2 ::
 *   FT_SUBGLYPH_FLAG_USE_MY_METRICS ::
 *
 */
#define FT_SUBGLYPH_FLAG_ARGS_ARE_WORDS 1
#define FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES 2
#define FT_SUBGLYPH_FLAG_ROUND_XY_TO_GRID 4
#define FT_SUBGLYPH_FLAG_SCALE 8
#define FT_SUBGLYPH_FLAG_XY_SCALE 0x40
#define FT_SUBGLYPH_FLAG_2X2 0x80
#define FT_SUBGLYPH_FLAG_USE_MY_METRICS 0x200

/**************************************************************************
 *
 * @function:
 *   FT_Get_SubGlyph_Info
 *
 * @description:
 *   Retrieve a description of a given subglyph.  Only use it if
 *   `glyph->format` is @FT_GLYPH_FORMAT_COMPOSITE; an error is returned
 *   otherwise.
 *
 * @input:
 *   glyph ::
 *     The source glyph slot.
 *
 *   sub_index ::
 *     The index of the subglyph.  Must be less than
 *     `glyph->num_subglyphs`.
 *
 * @output:
 *   p_index ::
 *     The glyph index of the subglyph.
 *
 *   p_flags ::
 *     The subglyph flags, see @FT_SUBGLYPH_FLAG_XXX.
 *
 *   p_arg1 ::
 *     The subglyph's first argument (if any).
 *
 *   p_arg2 ::
 *     The subglyph's second argument (if any).
 *
 *   p_transform ::
 *     The subglyph transformation (if any).
 *
 * @return:
 *   FreeType error code.  0~means success.
 *
 * @note:
 *   The values of `*p_arg1`, `*p_arg2`, and `*p_transform` must be
 *   interpreted depending on the flags returned in `*p_flags`.  See the
 *   OpenType specification for details.
 *
 *     https://docs.microsoft.com/en-us/typography/opentype/spec/glyf#composite-glyph-description
 *
 */
FT_EXPORT(FT_Error)
FT_Get_SubGlyph_Info(FT_GlyphSlot glyph, FT_UInt sub_index, FT_Int *p_index, FT_UInt *p_flags,
                     FT_Int *p_arg1, FT_Int *p_arg2, FT_Matrix *p_transform);

/**************************************************************************
 *
 * @section:
 *   layer_management
 *
 * @title:
 *   Glyph Layer Management
 *
 * @abstract:
 *   Retrieving and manipulating OpenType's 'COLR' table data.
 *
 * @description:
 *   The functions described here allow access of colored glyph layer data
 *   in OpenType's 'COLR' tables.
 */

/**************************************************************************
 *
 * @struct:
 *   FT_LayerIterator
 *
 * @description:
 *   This iterator object is needed for @FT_Get_Color_Glyph_Layer.
 *
 * @fields:
 *   num_layers ::
 *     The number of glyph layers for the requested glyph index.  Will be
 *     set by @FT_Get_Color_Glyph_Layer.
 *
 *   layer ::
 *     The current layer.  Will be set by @FT_Get_Color_Glyph_Layer.
 *
 *   p ::
 *     An opaque pointer into 'COLR' table data.  The caller must set this
 *     to `NULL` before the first call of @FT_Get_Color_Glyph_Layer.
 */
typedef struct FT_LayerIterator_ {
	FT_UInt num_layers;
	FT_UInt layer;
	FT_Byte *p;

} FT_LayerIterator;

/**************************************************************************
 *
 * @function:
 *   FT_Get_Color_Glyph_Layer
 *
 * @description:
 *   This is an interface to the 'COLR' table in OpenType fonts to
 *   iteratively retrieve the colored glyph layers associated with the
 *   current glyph slot.
 *
 *     https://docs.microsoft.com/en-us/typography/opentype/spec/colr
 *
 *   The glyph layer data for a given glyph index, if present, provides an
 *   alternative, multi-colour glyph representation: Instead of rendering
 *   the outline or bitmap with the given glyph index, glyphs with the
 *   indices and colors returned by this function are rendered layer by
 *   layer.
 *
 *   The returned elements are ordered in the z~direction from bottom to
 *   top; the 'n'th element should be rendered with the associated palette
 *   color and blended on top of the already rendered layers (elements 0,
 *   1, ..., n-1).
 *
 * @input:
 *   face ::
 *     A handle to the parent face object.
 *
 *   base_glyph ::
 *     The glyph index the colored glyph layers are associated with.
 *
 * @inout:
 *   iterator ::
 *     An @FT_LayerIterator object.  For the first call you should set
 *     `iterator->p` to `NULL`.  For all following calls, simply use the
 *     same object again.
 *
 * @output:
 *   aglyph_index ::
 *     The glyph index of the current layer.
 *
 *   acolor_index ::
 *     The color index into the font face's color palette of the current
 *     layer.  The value 0xFFFF is special; it doesn't reference a palette
 *     entry but indicates that the text foreground color should be used
 *     instead (to be set up by the application outside of FreeType).
 *
 *     The color palette can be retrieved with @FT_Palette_Select.
 *
 * @return:
 *   Value~1 if everything is OK.  If there are no more layers (or if there
 *   are no layers at all), value~0 gets returned.  In case of an error,
 *   value~0 is returned also.
 *
 * @note:
 *   This function is necessary if you want to handle glyph layers by
 *   yourself.  In particular, functions that operate with @FT_GlyphRec
 *   objects (like @FT_Get_Glyph or @FT_Glyph_To_Bitmap) don't have access
 *   to this information.
 *
 *   Note that @FT_Render_Glyph is able to handle colored glyph layers
 *   automatically if the @FT_LOAD_COLOR flag is passed to a previous call
 *   to @FT_Load_Glyph.  [This is an experimental feature.]
 *
 * @example:
 *   ```
 *     FT_Color*         palette;
 *     FT_LayerIterator  iterator;
 *
 *     FT_Bool  have_layers;
 *     FT_UInt  layer_glyph_index;
 *     FT_UInt  layer_color_index;
 *
 *
 *     error = FT_Palette_Select( face, palette_index, &palette );
 *     if ( error )
 *       palette = NULL;
 *
 *     iterator.p  = NULL;
 *     have_layers = FT_Get_Color_Glyph_Layer( face,
 *                                             glyph_index,
 *                                             &layer_glyph_index,
 *                                             &layer_color_index,
 *                                             &iterator );
 *
 *     if ( palette && have_layers )
 *     {
 *       do
 *       {
 *         FT_Color  layer_color;
 *
 *
 *         if ( layer_color_index == 0xFFFF )
 *           layer_color = text_foreground_color;
 *         else
 *           layer_color = palette[layer_color_index];
 *
 *         // Load and render glyph `layer_glyph_index', then
 *         // blend resulting pixmap (using color `layer_color')
 *         // with previously created pixmaps.
 *
 *       } while ( FT_Get_Color_Glyph_Layer( face,
 *                                           glyph_index,
 *                                           &layer_glyph_index,
 *                                           &layer_color_index,
 *                                           &iterator ) );
 *     }
 *   ```
 */
FT_EXPORT(FT_Bool)
FT_Get_Color_Glyph_Layer(FT_Face face, FT_UInt base_glyph, FT_UInt *aglyph_index,
                         FT_UInt *acolor_index, FT_LayerIterator *iterator);

/**************************************************************************
 *
 * @section:
 *   base_interface
 *
 */

/**************************************************************************
 *
 * @enum:
 *   FT_FSTYPE_XXX
 *
 * @description:
 *   A list of bit flags used in the `fsType` field of the OS/2 table in a
 *   TrueType or OpenType font and the `FSType` entry in a PostScript font.
 *   These bit flags are returned by @FT_Get_FSType_Flags; they inform
 *   client applications of embedding and subsetting restrictions
 *   associated with a font.
 *
 *   See
 *   https://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/FontPolicies.pdf
 *   for more details.
 *
 * @values:
 *   FT_FSTYPE_INSTALLABLE_EMBEDDING ::
 *     Fonts with no fsType bit set may be embedded and permanently
 *     installed on the remote system by an application.
 *
 *   FT_FSTYPE_RESTRICTED_LICENSE_EMBEDDING ::
 *     Fonts that have only this bit set must not be modified, embedded or
 *     exchanged in any manner without first obtaining permission of the
 *     font software copyright owner.
 *
 *   FT_FSTYPE_PREVIEW_AND_PRINT_EMBEDDING ::
 *     The font may be embedded and temporarily loaded on the remote
 *     system.  Documents containing Preview & Print fonts must be opened
 *     'read-only'; no edits can be applied to the document.
 *
 *   FT_FSTYPE_EDITABLE_EMBEDDING ::
 *     The font may be embedded but must only be installed temporarily on
 *     other systems.  In contrast to Preview & Print fonts, documents
 *     containing editable fonts may be opened for reading, editing is
 *     permitted, and changes may be saved.
 *
 *   FT_FSTYPE_NO_SUBSETTING ::
 *     The font may not be subsetted prior to embedding.
 *
 *   FT_FSTYPE_BITMAP_EMBEDDING_ONLY ::
 *     Only bitmaps contained in the font may be embedded; no outline data
 *     may be embedded.  If there are no bitmaps available in the font,
 *     then the font is unembeddable.
 *
 * @note:
 *   The flags are ORed together, thus more than a single value can be
 *   returned.
 *
 *   While the `fsType` flags can indicate that a font may be embedded, a
 *   license with the font vendor may be separately required to use the
 *   font in this way.
 */
#define FT_FSTYPE_INSTALLABLE_EMBEDDING 0x0000
#define FT_FSTYPE_RESTRICTED_LICENSE_EMBEDDING 0x0002
#define FT_FSTYPE_PREVIEW_AND_PRINT_EMBEDDING 0x0004
#define FT_FSTYPE_EDITABLE_EMBEDDING 0x0008
#define FT_FSTYPE_NO_SUBSETTING 0x0100
#define FT_FSTYPE_BITMAP_EMBEDDING_ONLY 0x0200

/**************************************************************************
 *
 * @function:
 *   FT_Get_FSType_Flags
 *
 * @description:
 *   Return the `fsType` flags for a font.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 * @return:
 *   The `fsType` flags, see @FT_FSTYPE_XXX.
 *
 * @note:
 *   Use this function rather than directly reading the `fs_type` field in
 *   the @PS_FontInfoRec structure, which is only guaranteed to return the
 *   correct results for Type~1 fonts.
 *
 * @since:
 *   2.3.8
 */
FT_EXPORT(FT_UShort)
FT_Get_FSType_Flags(FT_Face face);

/**************************************************************************
 *
 * @section:
 *   glyph_variants
 *
 * @title:
 *   Unicode Variation Sequences
 *
 * @abstract:
 *   The FreeType~2 interface to Unicode Variation Sequences (UVS), using
 *   the SFNT cmap format~14.
 *
 * @description:
 *   Many characters, especially for CJK scripts, have variant forms.  They
 *   are a sort of grey area somewhere between being totally irrelevant and
 *   semantically distinct; for this reason, the Unicode consortium decided
 *   to introduce Variation Sequences (VS), consisting of a Unicode base
 *   character and a variation selector instead of further extending the
 *   already huge number of characters.
 *
 *   Unicode maintains two different sets, namely 'Standardized Variation
 *   Sequences' and registered 'Ideographic Variation Sequences' (IVS),
 *   collected in the 'Ideographic Variation Database' (IVD).
 *
 *     https://unicode.org/Public/UCD/latest/ucd/StandardizedVariants.txt
 *     https://unicode.org/reports/tr37/ https://unicode.org/ivd/
 *
 *   To date (January 2017), the character with the most ideographic
 *   variations is U+9089, having 32 such IVS.
 *
 *   Three Mongolian Variation Selectors have the values U+180B-U+180D; 256
 *   generic Variation Selectors are encoded in the ranges U+FE00-U+FE0F
 *   and U+E0100-U+E01EF.  IVS currently use Variation Selectors from the
 *   range U+E0100-U+E01EF only.
 *
 *   A VS consists of the base character value followed by a single
 *   Variation Selector.  For example, to get the first variation of
 *   U+9089, you have to write the character sequence `U+9089 U+E0100`.
 *
 *   Adobe and MS decided to support both standardized and ideographic VS
 *   with a new cmap subtable (format~14).  It is an odd subtable because
 *   it is not a mapping of input code points to glyphs, but contains lists
 *   of all variations supported by the font.
 *
 *   A variation may be either 'default' or 'non-default' for a given font.
 *   A default variation is the one you will get for that code point if you
 *   look it up in the standard Unicode cmap.  A non-default variation is a
 *   different glyph.
 *
 */

/**************************************************************************
 *
 * @function:
 *   FT_Face_GetCharVariantIndex
 *
 * @description:
 *   Return the glyph index of a given character code as modified by the
 *   variation selector.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 *   charcode ::
 *     The character code point in Unicode.
 *
 *   variantSelector ::
 *     The Unicode code point of the variation selector.
 *
 * @return:
 *   The glyph index.  0~means either 'undefined character code', or
 *   'undefined selector code', or 'no variation selector cmap subtable',
 *   or 'current CharMap is not Unicode'.
 *
 * @note:
 *   If you use FreeType to manipulate the contents of font files directly,
 *   be aware that the glyph index returned by this function doesn't always
 *   correspond to the internal indices used within the file.  This is done
 *   to ensure that value~0 always corresponds to the 'missing glyph'.
 *
 *   This function is only meaningful if
 *     a) the font has a variation selector cmap sub table, and
 *     b) the current charmap has a Unicode encoding.
 *
 * @since:
 *   2.3.6
 */
FT_EXPORT(FT_UInt)
FT_Face_GetCharVariantIndex(FT_Face face, FT_ULong charcode, FT_ULong variantSelector);

/**************************************************************************
 *
 * @function:
 *   FT_Face_GetCharVariantIsDefault
 *
 * @description:
 *   Check whether this variation of this Unicode character is the one to
 *   be found in the charmap.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 *   charcode ::
 *     The character codepoint in Unicode.
 *
 *   variantSelector ::
 *     The Unicode codepoint of the variation selector.
 *
 * @return:
 *   1~if found in the standard (Unicode) cmap, 0~if found in the variation
 *   selector cmap, or -1 if it is not a variation.
 *
 * @note:
 *   This function is only meaningful if the font has a variation selector
 *   cmap subtable.
 *
 * @since:
 *   2.3.6
 */
FT_EXPORT(FT_Int)
FT_Face_GetCharVariantIsDefault(FT_Face face, FT_ULong charcode, FT_ULong variantSelector);

/**************************************************************************
 *
 * @function:
 *   FT_Face_GetVariantSelectors
 *
 * @description:
 *   Return a zero-terminated list of Unicode variation selectors found in
 *   the font.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 * @return:
 *   A pointer to an array of selector code points, or `NULL` if there is
 *   no valid variation selector cmap subtable.
 *
 * @note:
 *   The last item in the array is~0; the array is owned by the @FT_Face
 *   object but can be overwritten or released on the next call to a
 *   FreeType function.
 *
 * @since:
 *   2.3.6
 */
FT_EXPORT(FT_UInt32 *)
FT_Face_GetVariantSelectors(FT_Face face);

/**************************************************************************
 *
 * @function:
 *   FT_Face_GetVariantsOfChar
 *
 * @description:
 *   Return a zero-terminated list of Unicode variation selectors found for
 *   the specified character code.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 *   charcode ::
 *     The character codepoint in Unicode.
 *
 * @return:
 *   A pointer to an array of variation selector code points that are
 *   active for the given character, or `NULL` if the corresponding list is
 *   empty.
 *
 * @note:
 *   The last item in the array is~0; the array is owned by the @FT_Face
 *   object but can be overwritten or released on the next call to a
 *   FreeType function.
 *
 * @since:
 *   2.3.6
 */
FT_EXPORT(FT_UInt32 *)
FT_Face_GetVariantsOfChar(FT_Face face, FT_ULong charcode);

/**************************************************************************
 *
 * @function:
 *   FT_Face_GetCharsOfVariant
 *
 * @description:
 *   Return a zero-terminated list of Unicode character codes found for the
 *   specified variation selector.
 *
 * @input:
 *   face ::
 *     A handle to the source face object.
 *
 *   variantSelector ::
 *     The variation selector code point in Unicode.
 *
 * @return:
 *   A list of all the code points that are specified by this selector
 *   (both default and non-default codes are returned) or `NULL` if there
 *   is no valid cmap or the variation selector is invalid.
 *
 * @note:
 *   The last item in the array is~0; the array is owned by the @FT_Face
 *   object but can be overwritten or released on the next call to a
 *   FreeType function.
 *
 * @since:
 *   2.3.6
 */
FT_EXPORT(FT_UInt32 *)
FT_Face_GetCharsOfVariant(FT_Face face, FT_ULong variantSelector);

/**************************************************************************
 *
 * @section:
 *   computations
 *
 * @title:
 *   Computations
 *
 * @abstract:
 *   Crunching fixed numbers and vectors.
 *
 * @description:
 *   This section contains various functions used to perform computations
 *   on 16.16 fixed-float numbers or 2d vectors.
 *
 *   **Attention**: Most arithmetic functions take `FT_Long` as arguments.
 *   For historical reasons, FreeType was designed under the assumption
 *   that `FT_Long` is a 32-bit integer; results can thus be undefined if
 *   the arguments don't fit into 32 bits.
 *
 * @order:
 *   FT_MulDiv
 *   FT_MulFix
 *   FT_DivFix
 *   FT_RoundFix
 *   FT_CeilFix
 *   FT_FloorFix
 *   FT_Vector_Transform
 *   FT_Matrix_Multiply
 *   FT_Matrix_Invert
 *
 */

/**************************************************************************
 *
 * @function:
 *   FT_MulDiv
 *
 * @description:
 *   Compute `(a*b)/c` with maximum accuracy, using a 64-bit intermediate
 *   integer whenever necessary.
 *
 *   This function isn't necessarily as fast as some processor-specific
 *   operations, but is at least completely portable.
 *
 * @input:
 *   a ::
 *     The first multiplier.
 *
 *   b ::
 *     The second multiplier.
 *
 *   c ::
 *     The divisor.
 *
 * @return:
 *   The result of `(a*b)/c`.  This function never traps when trying to
 *   divide by zero; it simply returns 'MaxInt' or 'MinInt' depending on
 *   the signs of `a` and `b`.
 */
FT_EXPORT(FT_Long)
FT_MulDiv(FT_Long a, FT_Long b, FT_Long c);

/**************************************************************************
 *
 * @function:
 *   FT_MulFix
 *
 * @description:
 *   Compute `(a*b)/0x10000` with maximum accuracy.  Its main use is to
 *   multiply a given value by a 16.16 fixed-point factor.
 *
 * @input:
 *   a ::
 *     The first multiplier.
 *
 *   b ::
 *     The second multiplier.  Use a 16.16 factor here whenever possible
 *     (see note below).
 *
 * @return:
 *   The result of `(a*b)/0x10000`.
 *
 * @note:
 *   This function has been optimized for the case where the absolute value
 *   of `a` is less than 2048, and `b` is a 16.16 scaling factor.  As this
 *   happens mainly when scaling from notional units to fractional pixels
 *   in FreeType, it resulted in noticeable speed improvements between
 *   versions 2.x and 1.x.
 *
 *   As a conclusion, always try to place a 16.16 factor as the _second_
 *   argument of this function; this can make a great difference.
 */
FT_EXPORT(FT_Long)
FT_MulFix(FT_Long a, FT_Long b);

/**************************************************************************
 *
 * @function:
 *   FT_DivFix
 *
 * @description:
 *   Compute `(a*0x10000)/b` with maximum accuracy.  Its main use is to
 *   divide a given value by a 16.16 fixed-point factor.
 *
 * @input:
 *   a ::
 *     The numerator.
 *
 *   b ::
 *     The denominator.  Use a 16.16 factor here.
 *
 * @return:
 *   The result of `(a*0x10000)/b`.
 */
FT_EXPORT(FT_Long)
FT_DivFix(FT_Long a, FT_Long b);

/**************************************************************************
 *
 * @function:
 *   FT_RoundFix
 *
 * @description:
 *   Round a 16.16 fixed number.
 *
 * @input:
 *   a ::
 *     The number to be rounded.
 *
 * @return:
 *   `a` rounded to the nearest 16.16 fixed integer, halfway cases away
 *   from zero.
 *
 * @note:
 *   The function uses wrap-around arithmetic.
 */
FT_EXPORT(FT_Fixed)
FT_RoundFix(FT_Fixed a);

/**************************************************************************
 *
 * @function:
 *   FT_CeilFix
 *
 * @description:
 *   Compute the smallest following integer of a 16.16 fixed number.
 *
 * @input:
 *   a ::
 *     The number for which the ceiling function is to be computed.
 *
 * @return:
 *   `a` rounded towards plus infinity.
 *
 * @note:
 *   The function uses wrap-around arithmetic.
 */
FT_EXPORT(FT_Fixed)
FT_CeilFix(FT_Fixed a);

/**************************************************************************
 *
 * @function:
 *   FT_FloorFix
 *
 * @description:
 *   Compute the largest previous integer of a 16.16 fixed number.
 *
 * @input:
 *   a ::
 *     The number for which the floor function is to be computed.
 *
 * @return:
 *   `a` rounded towards minus infinity.
 */
FT_EXPORT(FT_Fixed)
FT_FloorFix(FT_Fixed a);

/**************************************************************************
 *
 * @function:
 *   FT_Vector_Transform
 *
 * @description:
 *   Transform a single vector through a 2x2 matrix.
 *
 * @inout:
 *   vector ::
 *     The target vector to transform.
 *
 * @input:
 *   matrix ::
 *     A pointer to the source 2x2 matrix.
 *
 * @note:
 *   The result is undefined if either `vector` or `matrix` is invalid.
 */
FT_EXPORT(void)
FT_Vector_Transform(FT_Vector *vector, const FT_Matrix *matrix);

/**************************************************************************
 *
 * @section:
 *   version
 *
 * @title:
 *   FreeType Version
 *
 * @abstract:
 *   Functions and macros related to FreeType versions.
 *
 * @description:
 *   Note that those functions and macros are of limited use because even a
 *   new release of FreeType with only documentation changes increases the
 *   version number.
 *
 * @order:
 *   FT_Library_Version
 *
 *   FREETYPE_MAJOR
 *   FREETYPE_MINOR
 *   FREETYPE_PATCH
 *
 *   FT_Face_CheckTrueTypePatents
 *   FT_Face_SetUnpatentedHinting
 *
 */

/**************************************************************************
 *
 * @enum:
 *   FREETYPE_XXX
 *
 * @description:
 *   These three macros identify the FreeType source code version.  Use
 *   @FT_Library_Version to access them at runtime.
 *
 * @values:
 *   FREETYPE_MAJOR ::
 *     The major version number.
 *   FREETYPE_MINOR ::
 *     The minor version number.
 *   FREETYPE_PATCH ::
 *     The patch level.
 *
 * @note:
 *   The version number of FreeType if built as a dynamic link library with
 *   the 'libtool' package is _not_ controlled by these three macros.
 *
 */
#define FREETYPE_MAJOR 2
#define FREETYPE_MINOR 10
#define FREETYPE_PATCH 1

/**************************************************************************
 *
 * @function:
 *   FT_Library_Version
 *
 * @description:
 *   Return the version of the FreeType library being used.  This is useful
 *   when dynamically linking to the library, since one cannot use the
 *   macros @FREETYPE_MAJOR, @FREETYPE_MINOR, and @FREETYPE_PATCH.
 *
 * @input:
 *   library ::
 *     A source library handle.
 *
 * @output:
 *   amajor ::
 *     The major version number.
 *
 *   aminor ::
 *     The minor version number.
 *
 *   apatch ::
 *     The patch version number.
 *
 * @note:
 *   The reason why this function takes a `library` argument is because
 *   certain programs implement library initialization in a custom way that
 *   doesn't use @FT_Init_FreeType.
 *
 *   In such cases, the library version might not be available before the
 *   library object has been created.
 */
FT_EXPORT(void)
FT_Library_Version(FT_Library library, FT_Int *amajor, FT_Int *aminor, FT_Int *apatch);

/**************************************************************************
 *
 * @function:
 *   FT_Face_CheckTrueTypePatents
 *
 * @description:
 *   Deprecated, does nothing.
 *
 * @input:
 *   face ::
 *     A face handle.
 *
 * @return:
 *   Always returns false.
 *
 * @note:
 *   Since May 2010, TrueType hinting is no longer patented.
 *
 * @since:
 *   2.3.5
 */
FT_EXPORT(FT_Bool)
FT_Face_CheckTrueTypePatents(FT_Face face);

/**************************************************************************
 *
 * @function:
 *   FT_Face_SetUnpatentedHinting
 *
 * @description:
 *   Deprecated, does nothing.
 *
 * @input:
 *   face ::
 *     A face handle.
 *
 *   value ::
 *     New boolean setting.
 *
 * @return:
 *   Always returns false.
 *
 * @note:
 *   Since May 2010, TrueType hinting is no longer patented.
 *
 * @since:
 *   2.3.5
 */
FT_EXPORT(FT_Bool)
FT_Face_SetUnpatentedHinting(FT_Face face, FT_Bool value);

/* */

FT_END_HEADER

#endif /* FREETYPE_H_ */

/* END */
